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=={{header|F_Sharp|F#}}== |
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<lang fsharp> |
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(* |
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Generate the data set |
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Nigel Galloway February 22nd., 2017 |
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*) |
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</lang> |
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=={{header|Haskell}}== |
=={{header|Haskell}}== |
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<lang Haskell>import Data.Function (on) |
<lang Haskell>import Data.Function (on) |
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Revision as of 11:36, 22 February 2017
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Find solutions to the sum to one hundred puzzle.
Add (insert) the mathematical
operators + or ─ (plus
or minus) before any of the digits in the
decimal numeric string 123456789 such that the
resulting mathematical expression adds up to a
particular sum (in this iconic case, 100).
Example:
123 + 4 - 5 + 67 - 89 = 100
Show all output here.
- Show all solutions that sum to 100
- Show the sum that has the maximum number of solutions (from zero to infinity*)
- Show the lowest positive sum that can't be expressed (has no solutions), using the rules for this task
- Show the ten highest numbers that can be expressed using the rules for this task (extra credit)
An example of a sum that can't be expressed (within the rules of this task) is: 5074
which, of course, is not the lowest positive sum that can't be expressed.
* (where infinity would be a relatively small 123,456,789)
ALGOL 68
<lang algol68>BEGIN
# find the numbers the string 123456789 ( with "+/-" optionally inserted # # before each digit ) can generate #
# experimentation shows that the largest hundred numbers that can be # # generated are are greater than or equal to 56795 # # as we can't declare an array with bounds -123456789 : 123456789 in # # Algol 68G, we use -60000 : 60000 and keep counts for the top hundred #
INT max number = 60 000; [ - max number : max number ]STRING solutions; [ - max number : max number ]INT count; FOR i FROM LWB solutions TO UPB solutions DO solutions[ i ] := ""; count[ i ] := 0 OD;
# calculate the numbers ( up to max number ) we can generate and the strings leading to them #
# also determine the largest numbers we can generate #
[ 100 ]INT largest;
[ 100 ]INT largest count;
INT impossible number = - 999 999 999;
FOR i FROM LWB largest TO UPB largest DO
largest [ i ] := impossible number;
largest count[ i ] := 0
OD;
[ 1 : 18 ]CHAR sum string := ".1.2.3.4.5.6.7.8.9";
[]CHAR sign char = []CHAR( "-", " ", "+" )[ AT -1 ];
# we don't distinguish between strings starting "+1" and starting " 1" #
FOR s1 FROM -1 TO 0 DO
sum string[ 1 ] := sign char[ s1 ];
FOR s2 FROM -1 TO 1 DO
sum string[ 3 ] := sign char[ s2 ];
FOR s3 FROM -1 TO 1 DO
sum string[ 5 ] := sign char[ s3 ];
FOR s4 FROM -1 TO 1 DO
sum string[ 7 ] := sign char[ s4 ];
FOR s5 FROM -1 TO 1 DO
sum string[ 9 ] := sign char[ s5 ];
FOR s6 FROM -1 TO 1 DO
sum string[ 11 ] := sign char[ s6 ];
FOR s7 FROM -1 TO 1 DO
sum string[ 13 ] := sign char[ s7 ];
FOR s8 FROM -1 TO 1 DO
sum string[ 15 ] := sign char[ s8 ];
FOR s9 FROM -1 TO 1 DO
sum string[ 17 ] := sign char[ s9 ];
INT number := 0;
INT part := IF s1 < 0 THEN -1 ELSE 1 FI;
IF s2 = 0 THEN part *:= 10 +:= 2 * SIGN part ELSE number +:= part; part := 2 * s2 FI;
IF s3 = 0 THEN part *:= 10 +:= 3 * SIGN part ELSE number +:= part; part := 3 * s3 FI;
IF s4 = 0 THEN part *:= 10 +:= 4 * SIGN part ELSE number +:= part; part := 4 * s4 FI;
IF s5 = 0 THEN part *:= 10 +:= 5 * SIGN part ELSE number +:= part; part := 5 * s5 FI;
IF s6 = 0 THEN part *:= 10 +:= 6 * SIGN part ELSE number +:= part; part := 6 * s6 FI;
IF s7 = 0 THEN part *:= 10 +:= 7 * SIGN part ELSE number +:= part; part := 7 * s7 FI;
IF s8 = 0 THEN part *:= 10 +:= 8 * SIGN part ELSE number +:= part; part := 8 * s8 FI;
IF s9 = 0 THEN part *:= 10 +:= 9 * SIGN part ELSE number +:= part; part := 9 * s9 FI;
number +:= part;
IF number >= LWB solutions
AND number <= UPB solutions
THEN
solutions[ number ] +:= ";" + sum string;
count [ number ] +:= 1
FI;
BOOL inserted := FALSE;
FOR l pos FROM LWB largest TO UPB largest WHILE NOT inserted DO
IF number > largest[ l pos ] THEN
# found a new larger number #
FOR m pos FROM UPB largest BY -1 TO l pos + 1 DO
largest [ m pos ] := largest [ m pos - 1 ];
largest count[ m pos ] := largest count[ m pos - 1 ]
OD;
largest [ l pos ] := number;
largest count[ l pos ] := 1;
inserted := TRUE
ELIF number = largest[ l pos ] THEN
# have another way of generating this number #
largest count[ l pos ] +:= 1;
inserted := TRUE
FI
OD
OD
OD
OD
OD
OD
OD
OD
OD
OD;
# show the solutions for 100 #
print( ( "100 has ", whole( count[ 100 ], 0 ), " solutions:" ) );
STRING s := solutions[ 100 ];
FOR s pos FROM LWB s TO UPB s DO
IF s[ s pos ] = ";" THEN print( ( newline, " " ) )
ELIF s[ s pos ] /= " " THEN print( ( s[ s pos ] ) )
FI
OD;
print( ( newline ) );
# find the number with the most solutions #
INT max solutions := 0;
INT number with max := LWB count - 1;
FOR n FROM 0 TO max number DO
IF count[ n ] > max solutions THEN
max solutions := count[ n ];
number with max := n
FI
OD;
FOR n FROM LWB largest count TO UPB largest count DO
IF largest count[ n ] > max solutions THEN
max solutions := largest count[ n ];
number with max := largest[ n ]
FI
OD;
print( ( whole( number with max, 0 ), " has the maximum number of solutions: ", whole( max solutions, 0 ), newline ) );
# find the smallest positive number that has no solutions #
BOOL have solutions := TRUE;
FOR n FROM 0 TO max number
WHILE IF NOT ( have solutions := count[ n ] > 0 )
THEN print( ( whole( n, 0 ), " is the lowest positive number with no solutions", newline ) )
FI;
have solutions
DO SKIP OD;
IF have solutions
THEN print( ( "All positive numbers up to ", whole( max number, 0 ), " have solutions", newline ) )
FI;
print( ( "The 10 largest numbers that can be generated are:", newline ) );
FOR t pos FROM 1 TO 10 DO
print( ( " ", whole( largest[ t pos ], 0 ) ) )
OD;
print( ( newline ) )
END</lang>
- Output:
100 has 12 solutions:
-1+2-3+4+5+6+78+9
12-3-4+5-6+7+89
123-4-5-6-7+8-9
123-45-67+89
123+4-5+67-89
123+45-67+8-9
12+3-4+5+67+8+9
12+3+4+5-6-7+89
1+23-4+56+7+8+9
1+23-4+5+6+78-9
1+2+3-4+5+6+78+9
1+2+34-5+67-8+9
9 has the maximum number of solutions: 46
211 is the lowest positive number with no solutions
The 10 largest numbers that can be generated are:
123456789 23456790 23456788 12345687 12345669 3456801 3456792 3456790 3456788 3456786
AppleScript
AppleScript is essentially out of its depth at this scale. The first task (number of distinct paths to 100) is accessible within a few seconds. Subsequent tasks, however, terminate only (if at all) after impractical amounts of time. Note the contrast with the lighter and more optimised JavaScript interpreter, which takes less than half a second to return full results for all the listed tasks. <lang AppleScript>use framework "Foundation" -- for basic NSArray sort
property pSigns : {1, 0, -1} --> ( + | unsigned | - ) property plst100 : {"Sums to 100:", ""} property plstSums : {} property plstSumsSorted : missing value property plstSumGroups : missing value
-- data Sign :: [ 1 | 0 | -1 ] = ( Plus | Unsigned | Minus ) -- asSum :: [Sign] -> Int on asSum(xs)
script
on lambda(a, sign, i)
if sign ≠ 0 then
{digits:{}, n:(n of a) + (sign * ((i & digits of a) as string as integer))}
else
{digits:{i} & (digits of a), n:n of a}
end if
end lambda
end script
set rec to foldr(result, {digits:{}, n:0}, xs)
set ds to digits of rec
if length of ds > 0 then
(n of rec) + (ds as string as integer)
else
n of rec
end if
end asSum
-- data Sign :: [ 1 | 0 | -1 ] = ( Plus | Unisigned | Minus ) -- asString :: [Sign] -> String on asString(xs)
script
on lambda(a, sign, i)
set d to i as string
if sign ≠ 0 then
if sign > 0 then
a & " +" & d
else
a & " -" & d
end if
else
a & d
end if
end lambda
end script
foldl(result, "", xs)
end asString
-- sumsTo100 :: () -> String on sumsTo100()
-- From first permutation without leading '+' (3 ^ 8) to end of universe (3 ^ 9)
repeat with i from 6561 to 19683
set xs to nthPermutationWithRepn(pSigns, 9, i)
if asSum(xs) = 100 then set end of plst100 to asString(xs)
end repeat
intercalate(linefeed, plst100)
end sumsTo100
-- mostCommonSum :: () -> String
on mostCommonSum()
-- From first permutation without leading '+' (3 ^ 8) to end of universe (3 ^ 9)
repeat with i from 6561 to 19683
set intSum to asSum(nthPermutationWithRepn(pSigns, 9, i))
if intSum ≥ 0 then set end of plstSums to intSum
end repeat
set plstSumsSorted to sort(plstSums)
set plstSumGroups to group(plstSumsSorted)
script groupLength
on lambda(a, b)
set intA to length of a
set intB to length of b
if intA < intB then
-1
else if intA > intB then
1
else
0
end if
end lambda
end script
set lstMaxSum to maximumBy(groupLength, plstSumGroups)
intercalate(linefeed, {"Most common sum: " & item 1 of lstMaxSum, "Number of instances: " & length of lstMaxSum})
end mostCommonSum
-- TEST ----------------------------------------------------------------------
on run
return sumsTo100() -- Also returns a value, but slow: -- mostCommonSum()
end run
-- GENERIC FUNCTIONS ---------------------------------------------------------
-- nthPermutationWithRepn :: [a] -> Int -> Int -> [a] on nthPermutationWithRepn(xs, groupSize, iIndex)
set intBase to length of xs
set intSetSize to intBase ^ groupSize
if intBase < 1 or iIndex > intSetSize then
{}
else
set baseElems to inBaseElements(xs, iIndex)
set intZeros to groupSize - (length of baseElems)
if intZeros > 0 then
replicate(intZeros, item 1 of xs) & baseElems
else
baseElems
end if
end if
end nthPermutationWithRepn
-- inBaseElements :: [a] -> Int -> [String] on inBaseElements(xs, n)
set intBase to length of xs
script nextDigit
on lambda(residue)
set {divided, remainder} to quotRem(residue, intBase)
{valid:divided > 0, value:(item (remainder + 1) of xs), new:divided}
end lambda
end script
reverse of unfoldr(nextDigit, n)
end inBaseElements
-- sort :: [a] -> [a] on sort(lst)
((current application's NSArray's arrayWithArray:lst)'s ¬
sortedArrayUsingSelector:"compare:") as list
end sort
-- maximumBy :: (a -> a -> Ordering) -> [a] -> a on maximumBy(f, xs)
set cmp to mReturn(f)
script max
on lambda(a, b)
if a is missing value or cmp's lambda(a, b) < 0 then
b
else
a
end if
end lambda
end script
foldl(max, missing value, xs)
end maximumBy
-- group :: Eq a => [a] -> a on group(xs)
script eq
on lambda(a, b)
a = b
end lambda
end script
groupBy(eq, xs)
end group
-- groupBy :: (a -> a -> Bool) -> [a] -> a on groupBy(f, xs)
set mf to mReturn(f)
script enGroup
on lambda(a, x)
if length of (active of a) > 0 then
set h to item 1 of active of a
else
set h to missing value
end if
if h is not missing value and mf's lambda(h, x) then
{active:(active of a) & x, sofar:sofar of a}
else
{active:{x}, sofar:(sofar of a) & {active of a}}
end if
end lambda
end script
if length of xs > 0 then
set dct to foldl(enGroup, {active:{item 1 of xs}, sofar:{}}, tail(xs))
if length of (active of dct) > 0 then
sofar of dct & {active of dct}
else
sofar of dct
end if
else
{}
end if
end groupBy
-- tail :: [a] -> [a] on tail(xs)
if length of xs > 1 then
items 2 thru -1 of xs
else
{}
end if
end tail
-- intercalate :: Text -> [Text] -> Text
on intercalate(strText, lstText)
set {dlm, my text item delimiters} to {my text item delimiters, strText}
set strJoined to lstText as text
set my text item delimiters to dlm
return strJoined
end intercalate
-- quotRem :: Integral a => a -> a -> (a, a) on quotRem(m, n)
{m div n, m mod n}
end quotRem
-- replicate :: Int -> a -> [a] on replicate(n, a)
set out to {}
if n < 1 then return out
set dbl to {a}
repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
-- foldr :: (a -> b -> a) -> a -> [b] -> a on foldr(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from lng to 1 by -1
set v to lambda(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldr
-- foldl :: (a -> b -> a) -> a -> [b] -> a on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to lambda(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- unfoldr :: (b -> Maybe (a, b)) -> b -> [a] on unfoldr(f, v)
set mf to mReturn(f)
set lst to {}
set recM to mf's lambda(v)
repeat while (valid of recM) is true
set end of lst to value of recM
set recM to mf's lambda(new of recM)
end repeat
lst & value of recM
end unfoldr
-- until :: (a -> Bool) -> (a -> a) -> a -> a on |until|(p, f, x)
set mp to mReturn(p)
set v to x
tell mReturn(f)
repeat until mp's lambda(v)
set v to lambda(v)
end repeat
end tell
return v
end |until|
-- range :: Int -> Int -> [Int] on range(m, n)
if n < m then
set d to -1
else
set d to 1
end if
set lst to {}
repeat with i from m to n by d
set end of lst to i
end repeat
return lst
end range
-- map :: (a -> b) -> [a] -> [b] on map(f, xs)
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to lambda(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- Lift 2nd class handler function into 1st class script wrapper
-- mReturn :: Handler -> Script
on mReturn(f)
if class of f is script then
f
else
script
property lambda : f
end script
end if
end mReturn</lang>
- Output:
Sums to 100: 1 +2 +34 -5 +67 -8 +9 1 +2 +3 -4 +5 +6 +78 +9 1 +23 -4 +5 +6 +78 -9 1 +23 -4 +56 +7 +8 +9 12 +3 +4 +5 -6 -7 +89 12 +3 -4 +5 +67 +8 +9 123 +45 -67 +8 -9 123 +4 -5 +67 -89 123 -45 -67 +89 123 -4 -5 -6 -7 +8 -9 12 -3 -4 +5 -6 +7 +89 -1 +2 -3 +4 +5 +6 +78 +9
C#
<lang csharp>using System; using System.Collections.Generic; using System.Linq;
class Program {
static void Main(string[] args)
{
// All unique expressions that have a plus sign in front of the 1; calculated in parallel
var expressionsPlus = Enumerable.Range(0, (int)Math.Pow(3, 8)).AsParallel().Select(i => new Expression(i, 1));
// All unique expressions that have a minus sign in front of the 1; calculated in parallel
var expressionsMinus = Enumerable.Range(0, (int)Math.Pow(3, 8)).AsParallel().Select(i => new Expression(i, -1));
var expressions = expressionsPlus.Concat(expressionsMinus);
var results = new Dictionary<int, List<Expression>>();
foreach (var e in expressions)
{
if (results.Keys.Contains(e.Value))
results[e.Value].Add(e);
else
results[e.Value] = new List<Expression>() { e };
}
Console.WriteLine("Show all solutions that sum to 100");
foreach (Expression e in results[100])
Console.WriteLine(" " + e);
Console.WriteLine("Show the sum that has the maximum number of solutions (from zero to infinity)");
var summary = results.Keys.Select(k => new Tuple<int, int>(k, results[k].Count));
var maxSols = summary.Aggregate((a, b) => a.Item2 > b.Item2 ? a : b);
Console.WriteLine(" The sum " + maxSols.Item1 + " has " + maxSols.Item2 + " solutions.");
Console.WriteLine("Show the lowest positive sum that can't be expressed (has no solutions), using the rules for this task");
var lowestPositive = Enumerable.Range(1, int.MaxValue).First(x => !results.Keys.Contains(x));
Console.WriteLine(" " + lowestPositive);
Console.WriteLine("Show the ten highest numbers that can be expressed using the rules for this task (extra credit)");
var highest = from k in results.Keys
orderby k descending
select k;
foreach (var x in highest.Take(10))
Console.WriteLine(" " + x);
}
} public enum Operations { Plus, Minus, Join }; public class Expression {
protected Operations[] Gaps;
// 123456789 => there are 8 "gaps" between each number
/// with 3 possibilities for each gap: plus, minus, or join
public int Value; // What this expression sums up to
protected int _one;
public Expression(int serial, int one)
{
_one = one;
Gaps = new Operations[8];
// This represents "serial" as a base 3 number, each Gap expression being a base-three digit
int divisor = 2187; // == Math.Pow(3,7)
int times;
for (int i = 0; i < 8; i++)
{
times = Math.DivRem(serial, divisor, out serial);
divisor /= 3;
if (times == 0)
Gaps[i] = Operations.Join;
else if (times == 1)
Gaps[i] = Operations.Minus;
else
Gaps[i] = Operations.Plus;
}
// go ahead and calculate the value of this expression
// because this is going to be done in a parallel thread (save time)
Value = Evaluate();
}
public override string ToString()
{
string ret = _one.ToString();
for (int i = 0; i < 8; i++)
{
switch (Gaps[i])
{
case Operations.Plus:
ret += "+";
break;
case Operations.Minus:
ret += "-";
break;
}
ret += (i + 2);
}
return ret;
}
private int Evaluate()
/* Calculate what this expression equals */
{
var numbers = new int[9];
int nc = 0;
var operations = new List<Operations>();
int a = 1;
for (int i = 0; i < 8; i++)
{
if (Gaps[i] == Operations.Join)
a = a * 10 + (i + 2);
else
{
if (a > 0)
{
if (nc == 0)
a *= _one;
numbers[nc++] = a;
a = i + 2;
}
operations.Add(Gaps[i]);
}
}
if (nc == 0)
a *= _one;
numbers[nc++] = a;
int ni = 0;
int left = numbers[ni++];
foreach (var operation in operations)
{
int right = numbers[ni++];
if (operation == Operations.Plus)
left = left + right;
else
left = left - right;
}
return left;
}
}</lang>
- Output:
Show all solutions that sum to 100 123-45-67+89 123-4-5-6-7+8-9 123+45-67+8-9 123+4-5+67-89 12-3-4+5-6+7+89 12+3-4+5+67+8+9 12+3+4+5-6-7+89 1+23-4+5+6+78-9 1+23-4+56+7+8+9 1+2+34-5+67-8+9 1+2+3-4+5+6+78+9 -1+2-3+4+5+6+78+9 Show the sum that has the maximum number of solutions (from zero to infinity) The sum 9 has 46 solutions. Show the lowest positive sum that can't be expressed (has no solutions), using the rules for this task 211 Show the ten highest numbers that can be expressed using the rules for this task (extra credit) 123456789 23456790 23456788 12345687 12345669 3456801 3456792 3456790 3456788 3456786
Elixir
<lang elixir>defmodule Sum do
def to(val) do
generate
|> Enum.map(&{eval(&1), &1})
|> Enum.filter(fn {v, _s} -> v==val end)
|> Enum.each(&IO.inspect &1)
end
def max_solve do
generate
|> Enum.group_by(&eval &1)
|> Enum.filter_map(fn {k,_} -> k>=0 end, fn {k,v} -> {length(v),k} end)
|> Enum.max
|> fn {len,sum} -> IO.puts "sum of #{sum} has the maximum number of solutions : #{len}" end.()
end
def min_solve do
solve = generate |> Enum.group_by(&eval &1)
Stream.iterate(1, &(&1+1))
|> Enum.find(fn n -> solve[n]==nil end)
|> fn sum -> IO.puts "lowest positive sum that can't be expressed : #{sum}" end.()
end
def highest_sums(n\\10) do
IO.puts "highest sums :"
generate
|> Enum.map(&eval &1)
|> Enum.uniq
|> Enum.sort_by(fn sum -> -sum end)
|> Enum.take(n)
|> IO.inspect
end
defp generate do
x = ["+", "-", ""]
for a <- ["-", ""], b <- x, c <- x, d <- x, e <- x, f <- x, g <- x, h <- x, i <- x,
do: "#{a}1#{b}2#{c}3#{d}4#{e}5#{f}6#{g}7#{h}8#{i}9"
end
defp eval(str), do: Code.eval_string(str) |> elem(0)
end
Sum.to(100) Sum.max_solve Sum.min_solve Sum.highest_sums</lang>
- Output:
{100, "-1+2-3+4+5+6+78+9"}
{100, "1+2+3-4+5+6+78+9"}
{100, "1+2+34-5+67-8+9"}
{100, "1+23-4+5+6+78-9"}
{100, "1+23-4+56+7+8+9"}
{100, "12+3+4+5-6-7+89"}
{100, "12+3-4+5+67+8+9"}
{100, "12-3-4+5-6+7+89"}
{100, "123+4-5+67-89"}
{100, "123+45-67+8-9"}
{100, "123-4-5-6-7+8-9"}
{100, "123-45-67+89"}
sum of 9 has the maximum number of solutions : 46
lowest positive sum that can't be expressed : 211
highest sums :
[123456789, 23456790, 23456788, 12345687, 12345669, 3456801, 3456792, 3456790,
3456788, 3456786]
F#
<lang fsharp> (* Generate the data set Nigel Galloway February 22nd., 2017
- )
</lang>
Haskell
<lang Haskell>import Data.Function (on) import Control.Arrow ((&&&)) import Data.Char (intToDigit) import Control.Monad (replicateM) import Data.List (nub, group, sort, sortBy, find, intercalate)
data Sign
= Unsigned | Plus | Minus deriving (Eq, Show)
universe :: (Int, Sign) universe =
zip [1 .. 9] <$> filter ((/= Plus) . head) (replicateM 9 [Unsigned, Plus, Minus])
allNonNegativeSums :: [Int] allNonNegativeSums = sort $ filter (>= 0) (asSum <$> universe)
uniqueNonNegativeSums :: [Int] uniqueNonNegativeSums = nub allNonNegativeSums
asSum :: [(Int, Sign)] -> Int asSum xs =
n +
(if null s
then 0
else read s :: Int)
where
(n, s) = foldr readSign (0, []) xs
readSign :: (Int, Sign) -> (Int, String) -> (Int, String)
readSign (i, x) (n, s)
| x == Unsigned = (n, intToDigit i : s)
| otherwise =
( (if x == Plus
then (+)
else (-))
n
(read (show i ++ s) :: Int)
, [])
asString :: [(Int, Sign)] -> String asString = foldr signedDigit []
where
signedDigit (i, x) s
| x == Unsigned = intToDigit i : s
| otherwise =
(if x == Plus
then " +"
else " -") ++
[intToDigit i] ++ s
main :: IO () main =
mapM_
putStrLn
[ "Sums to 100:\n"
, unlines $ asString <$> filter ((== 100) . asSum) universe
, "\n10 commonest sums [sum, number of routes to it]:\n"
, show
((head &&& length) <$>
take 10 (sortBy (on (flip compare) length) (group allNonNegativeSums)))
, "\nFirst positive integer not expressible as a sum of this kind:\n"
, maybeReport (find (uncurry (/=)) (zip [0 ..] uniqueNonNegativeSums))
, "\n10 largest sums:\n"
, show $ take 10 $ sortBy (flip compare) uniqueNonNegativeSums
, "\n"
]
where
maybeReport
:: Show a
=> Maybe (a, b) -> String
maybeReport (Just (x, _)) = show x
maybeReport _ = "No gaps found"</lang>
- Output:
(Run in Atom editor, through Script package)
Sums to 100: 123 +45 -67 +8 -9 123 +4 -5 +67 -89 123 -45 -67 +89 123 -4 -5 -6 -7 +8 -9 12 +3 +4 +5 -6 -7 +89 12 +3 -4 +5 +67 +8 +9 12 -3 -4 +5 -6 +7 +89 1 +23 -4 +56 +7 +8 +9 1 +23 -4 +5 +6 +78 -9 1 +2 +34 -5 +67 -8 +9 1 +2 +3 -4 +5 +6 +78 +9 -1 +2 -3 +4 +5 +6 +78 +9 10 commonest sums [sum, number of routes to it]: [(9,46),(27,44),(1,43),(15,43),(21,43),(45,42),(3,41),(5,40),(7,39),(17,39)] First positive integer not expressible as a sum of this kind: 211 10 largest sums: [123456789,23456790,23456788,12345687,12345669,3456801,3456792,3456790,3456788,3456786] [Finished in 1.237s]
JavaScript
ES5
<lang JavaScript>(function () {
'use strict';
// GENERIC FUNCTIONS ----------------------------------------------------
// permutationsWithRepetition :: Int -> [a] -> a var permutationsWithRepetition = function (n, as) { return as.length > 0 ? foldl1(curry(cartesianProduct)(as), replicate(n, as)) : []; };
// cartesianProduct :: [a] -> [b] -> a, b var cartesianProduct = function (xs, ys) { return [].concat.apply([], xs.map(function (x) { return [].concat.apply([], ys.map(function (y) { return [ [x].concat(y) ]; })); })); };
// curry :: ((a, b) -> c) -> a -> b -> c
var curry = function (f) {
return function (a) {
return function (b) {
return f(a, b);
};
};
};
// flip :: (a -> b -> c) -> b -> a -> c
var flip = function (f) {
return function (a, b) {
return f.apply(null, [b, a]);
};
};
// foldl1 :: (a -> a -> a) -> [a] -> a
var foldl1 = function (f, xs) {
return xs.length > 0 ? xs.slice(1)
.reduce(f, xs[0]) : [];
};
// replicate :: Int -> a -> [a]
var replicate = function (n, a) {
var v = [a],
o = [];
if (n < 1) return o;
while (n > 1) {
if (n & 1) o = o.concat(v);
n >>= 1;
v = v.concat(v);
}
return o.concat(v);
};
// group :: Eq a => [a] -> a var group = function (xs) { return groupBy(function (a, b) { return a === b; }, xs); };
// groupBy :: (a -> a -> Bool) -> [a] -> a var groupBy = function (f, xs) { var dct = xs.slice(1) .reduce(function (a, x) { var h = a.active.length > 0 ? a.active[0] : undefined, blnGroup = h !== undefined && f(h, x);
return {
active: blnGroup ? a.active.concat(x) : [x],
sofar: blnGroup ? a.sofar : a.sofar.concat([a.active])
};
}, {
active: xs.length > 0 ? [xs[0]] : [],
sofar: []
});
return dct.sofar.concat(dct.active.length > 0 ? [dct.active] : []);
};
// compare :: a -> a -> Ordering
var compare = function (a, b) {
return a < b ? -1 : a > b ? 1 : 0;
};
// on :: (b -> b -> c) -> (a -> b) -> a -> a -> c
var on = function (f, g) {
return function (a, b) {
return f(g(a), g(b));
};
};
// nub :: [a] -> [a]
var nub = function (xs) {
return nubBy(function (a, b) {
return a === b;
}, xs);
};
// nubBy :: (a -> a -> Bool) -> [a] -> [a]
var nubBy = function (p, xs) {
var x = xs.length ? xs[0] : undefined;
return x !== undefined ? [x].concat(nubBy(p, xs.slice(1)
.filter(function (y) {
return !p(x, y);
}))) : [];
};
// find :: (a -> Bool) -> [a] -> Maybe a
var find = function (f, xs) {
for (var i = 0, lng = xs.length; i < lng; i++) {
if (f(xs[i], i)) return xs[i];
}
return undefined;
};
// Int -> [a] -> [a]
var take = function (n, xs) {
return xs.slice(0, n);
};
// unlines :: [String] -> String
var unlines = function (xs) {
return xs.join('\n');
};
// show :: a -> String
var show = function (x) {
return JSON.stringify(x);
}; //, null, 2);
// head :: [a] -> a
var head = function (xs) {
return xs.length ? xs[0] : undefined;
};
// tail :: [a] -> [a]
var tail = function (xs) {
return xs.length ? xs.slice(1) : undefined;
};
// length :: [a] -> Int
var length = function (xs) {
return xs.length;
};
// SIGNED DIGIT SEQUENCES (mapped to sums and to strings)
// data Sign :: [ 0 | 1 | -1 ] = ( Unsigned | Plus | Minus )
// asSum :: [Sign] -> Int
var asSum = function (xs) {
var dct = xs.reduceRight(function (a, sign, i) {
var d = i + 1; // zero-based index to [1-9] positions
if (sign !== 0) {
// Sum increased, digits cleared
return {
digits: [],
n: a.n + sign * parseInt([d].concat(a.digits)
.join(), 10)
};
} else return { // Digits extended, sum unchanged
digits: [d].concat(a.digits),
n: a.n
};
}, {
digits: [],
n: 0
});
return dct.n + (
dct.digits.length > 0 ? parseInt(dct.digits.join(), 10) : 0
);
};
// data Sign :: [ 0 | 1 | -1 ] = ( Unsigned | Plus | Minus )
// asString :: [Sign] -> String
var asString = function (xs) {
var ns = xs.reduce(function (a, sign, i) {
var d = (i + 1)
.toString();
return sign === 0 ? a + d : a + (sign > 0 ? ' +' : ' -') + d;
}, );
return ns[0] === '+' ? tail(ns) : ns; };
// SUM T0 100 ------------------------------------------------------------
// universe :: Sign var universe = permutationsWithRepetition(9, [0, 1, -1]) .filter(function (x) { return x[0] !== 1; });
// allNonNegativeSums :: [Int]
var allNonNegativeSums = universe.map(asSum)
.filter(function (x) {
return x >= 0;
})
.sort();
// uniqueNonNegativeSums :: [Int] var uniqueNonNegativeSums = nub(allNonNegativeSums);
return ["Sums to 100:\n", unlines(universe.filter(function (x) {
return asSum(x) === 100;
})
.map(asString)),
"\n\n10 commonest sums (sum, followed by number of routes to it):\n",
show(take(10, group(allNonNegativeSums)
.sort(on(flip(compare), length))
.map(function (xs) {
return [xs[0], xs.length];
}))),
"\n\nFirst positive integer not expressible as a sum of this kind:\n",
show(find(function (x, i) {
return x !== i;
}, uniqueNonNegativeSums.sort(compare)) - 1), // zero-based index
"\n10 largest sums:\n",
show(take(10, uniqueNonNegativeSums.sort(flip(compare))))
].join('\n') + '\n';
})();</lang>
- Output:
(Run in Atom editor, through Script package)
Sums to 100: 123 +45 -67 +8 -9 123 +4 -5 +67 -89 123 -45 -67 +89 123 -4 -5 -6 -7 +8 -9 12 +3 +4 +5 -6 -7 +89 12 +3 -4 +5 +67 +8 +9 12 -3 -4 +5 -6 +7 +89 1 +23 -4 +56 +7 +8 +9 1 +23 -4 +5 +6 +78 -9 1 +2 +34 -5 +67 -8 +9 1 +2 +3 -4 +5 +6 +78 +9 -1 +2 -3 +4 +5 +6 +78 +9 10 commonest sums (sum, followed by number of routes to it): [[9,46],[27,44],[1,43],[15,43],[21,43],[45,42],[3,41],[5,40],[17,39],[7,39]] First positive integer not expressible as a sum of this kind: 211 10 largest sums: [123456789,23456790,23456788,12345687,12345669,3456801,3456792,3456790,3456788,3456786] [Finished in 0.381s]
ES6
<lang JavaScript>(() => {
'use strict';
// GENERIC FUNCTIONS ----------------------------------------------------
// permutationsWithRepetition :: Int -> [a] -> a const permutationsWithRepetition = (n, as) => as.length > 0 ? ( foldl1(curry(cartesianProduct)(as), replicate(n, as)) ) : [];
// cartesianProduct :: [a] -> [b] -> a, b const cartesianProduct = (xs, ys) => [].concat.apply([], xs.map(x => [].concat.apply([], ys.map(y => [[x].concat(y)]))));
// curry :: ((a, b) -> c) -> a -> b -> c const curry = f => a => b => f(a, b);
// flip :: (a -> b -> c) -> b -> a -> c const flip = f => (a, b) => f.apply(null, [b, a]);
// foldl1 :: (a -> a -> a) -> [a] -> a
const foldl1 = (f, xs) =>
xs.length > 0 ? xs.slice(1)
.reduce(f, xs[0]) : [];
// replicate :: Int -> a -> [a]
const replicate = (n, a) => {
let v = [a],
o = [];
if (n < 1) return o;
while (n > 1) {
if (n & 1) o = o.concat(v);
n >>= 1;
v = v.concat(v);
}
return o.concat(v);
};
// group :: Eq a => [a] -> a const group = xs => groupBy((a, b) => a === b, xs);
// groupBy :: (a -> a -> Bool) -> [a] -> a const groupBy = (f, xs) => { const dct = xs.slice(1) .reduce((a, x) => { const h = a.active.length > 0 ? a.active[0] : undefined, blnGroup = h !== undefined && f(h, x);
return {
active: blnGroup ? a.active.concat(x) : [x],
sofar: blnGroup ? a.sofar : a.sofar.concat([a.active])
};
}, {
active: xs.length > 0 ? [xs[0]] : [],
sofar: []
});
return dct.sofar.concat(dct.active.length > 0 ? [dct.active] : []);
};
// compare :: a -> a -> Ordering const compare = (a, b) => a < b ? -1 : (a > b ? 1 : 0);
// on :: (b -> b -> c) -> (a -> b) -> a -> a -> c const on = (f, g) => (a, b) => f(g(a), g(b));
// nub :: [a] -> [a] const nub = xs => nubBy((a, b) => a === b, xs);
// nubBy :: (a -> a -> Bool) -> [a] -> [a]
const nubBy = (p, xs) => {
const x = xs.length ? xs[0] : undefined;
return x !== undefined ? [x].concat(
nubBy(p, xs.slice(1)
.filter(y => !p(x, y)))
) : [];
};
// find :: (a -> Bool) -> [a] -> Maybe a
const find = (f, xs) => {
for (var i = 0, lng = xs.length; i < lng; i++) {
if (f(xs[i], i)) return xs[i];
}
return undefined;
}
// Int -> [a] -> [a] const take = (n, xs) => xs.slice(0, n);
// unlines :: [String] -> String
const unlines = xs => xs.join('\n');
// show :: a -> String const show = x => JSON.stringify(x); //, null, 2);
// head :: [a] -> a const head = xs => xs.length ? xs[0] : undefined;
// tail :: [a] -> [a] const tail = xs => xs.length ? xs.slice(1) : undefined;
// length :: [a] -> Int const length = xs => xs.length;
// SIGNED DIGIT SEQUENCES (mapped to sums and to strings)
// data Sign :: [ 0 | 1 | -1 ] = ( Unsigned | Plus | Minus )
// asSum :: [Sign] -> Int
const asSum = xs => {
const dct = xs.reduceRight((a, sign, i) => {
const d = i + 1; // zero-based index to [1-9] positions
if (sign !== 0) { // Sum increased, digits cleared
return {
digits: [],
n: a.n + (sign * parseInt([d].concat(a.digits)
.join(), 10))
};
} else return { // Digits extended, sum unchanged
digits: [d].concat(a.digits),
n: a.n
};
}, {
digits: [],
n: 0
});
return dct.n + (dct.digits.length > 0 ? (
parseInt(dct.digits.join(), 10)
) : 0);
};
// data Sign :: [ 0 | 1 | -1 ] = ( Unsigned | Plus | Minus )
// asString :: [Sign] -> String
const asString = xs => {
const ns = xs.reduce((a, sign, i) => {
const d = (i + 1)
.toString();
return (sign === 0 ? (
a + d
) : (a + (sign > 0 ? ' +' : ' -') + d));
}, );
return ns[0] === '+' ? tail(ns) : ns; };
// SUM T0 100 ------------------------------------------------------------
// universe :: Sign const universe = permutationsWithRepetition(9, [0, 1, -1]) .filter(x => x[0] !== 1);
// allNonNegativeSums :: [Int]
const allNonNegativeSums = universe.map(asSum)
.filter(x => x >= 0)
.sort();
// uniqueNonNegativeSums :: [Int] const uniqueNonNegativeSums = nub(allNonNegativeSums);
return [
"Sums to 100:\n",
unlines(universe.filter(x => asSum(x) === 100)
.map(asString)),
"\n\n10 commonest sums (sum, followed by number of routes to it):\n",
show(take(10, group(allNonNegativeSums)
.sort(on(flip(compare), length))
.map(xs => [xs[0], xs.length]))),
"\n\nFirst positive integer not expressible as a sum of this kind:\n",
show(find(
(x, i) => x !== i,
uniqueNonNegativeSums.sort(compare)
) - 1), // i is the the zero-based Array index.
"\n10 largest sums:\n",
show(take(10, uniqueNonNegativeSums.sort(flip(compare))))
].join('\n') + '\n';
})();</lang>
- Output:
(Run in Atom editor, through Script package)
Sums to 100: 123 +45 -67 +8 -9 123 +4 -5 +67 -89 123 -45 -67 +89 123 -4 -5 -6 -7 +8 -9 12 +3 +4 +5 -6 -7 +89 12 +3 -4 +5 +67 +8 +9 12 -3 -4 +5 -6 +7 +89 1 +23 -4 +56 +7 +8 +9 1 +23 -4 +5 +6 +78 -9 1 +2 +34 -5 +67 -8 +9 1 +2 +3 -4 +5 +6 +78 +9 -1 +2 -3 +4 +5 +6 +78 +9 10 commonest sums (sum, followed by number of routes to it): [[9,46],[27,44],[1,43],[15,43],[21,43],[45,42],[3,41],[5,40],[17,39],[7,39]] First positive integer not expressible as a sum of this kind: 211 10 largest sums: [123456789,23456790,23456788,12345687,12345669,3456801,3456792,3456790,3456788,3456786] [Finished in 0.382s]
Mathematica
Defining all possible sums and couting them:
<lang Mathematica>operations =
DeleteCases[Tuples[{"+", "-", ""}, 9], {x_, y__} /; x == "+"];
allsums =
Map[StringJoin[Riffle[#, CharacterRange["1", "9"]]] &, operations];
counts = CountsBy[allsums, ToExpression];</lang>
Sums to 100:
<lang Mathematica> TableForm@Select[allsums, ToExpression@# == 100 &] </lang>
- Output:
-1+2-3+4+5+6+78+9 1+2+3-4+5+6+78+9 1+2+34-5+67-8+9 1+23-4+5+6+78-9 1+23-4+56+7+8+9 12+3+4+5-6-7+89 12+3-4+5+67+8+9 12-3-4+5-6+7+89 123+4-5+67-89 123+45-67+8-9 123-4-5-6-7+8-9 123-45-67+89
Maximum number of solutions: <lang Mathematica> MaximalBy[counts, Identity] </lang>
- Output:
<|9 -> 46, -9 -> 46|>
First unsolvable: <lang Mathematica> i = 1; While[KeyExistsQ[counts, i], ++i]; i </lang>
- Output:
221
Ten largest sums: <lang Mathematica> TakeLargest[Keys@counts, 10] </lang>
- Output:
{123456789, 23456790, 23456788, 12345687, 12345669, 3456801, 3456792, 3456790, 3456788, 3456786}
Perl 6
<lang perl6>my @ops = ['-', ], |( [' + ', ' - ', ] xx 8 ); my @str = [X~] map { .Slip }, ( @ops Z 1..9 ); my %sol = @str.classify: *.subst( ' - ', ' -', :g )\
.subst( ' + ', ' ', :g ).words.sum;
my %count.push: %sol.map({ .value.elems => .key });
my $max_solutions = %count.max( + *.key ); my $first_unsolvable = first { %sol{$_} :!exists }, 1..*; my @two_largest_sums = %sol.keys.sort(-*)[^2];
given %sol{100}:p {
say "{.value.elems} solutions for sum {.key}:";
say " $_" for .value.list;
}
say .perl for :$max_solutions, :$first_unsolvable, :@two_largest_sums;</lang>
- Output:
12 solutions for sum 100:
-1 + 2 - 3 + 4 + 5 + 6 + 78 + 9
1 + 2 + 3 - 4 + 5 + 6 + 78 + 9
1 + 2 + 34 - 5 + 67 - 8 + 9
1 + 23 - 4 + 5 + 6 + 78 - 9
1 + 23 - 4 + 56 + 7 + 8 + 9
12 + 3 + 4 + 5 - 6 - 7 + 89
12 + 3 - 4 + 5 + 67 + 8 + 9
12 - 3 - 4 + 5 - 6 + 7 + 89
123 + 4 - 5 + 67 - 89
123 + 45 - 67 + 8 - 9
123 - 4 - 5 - 6 - 7 + 8 - 9
123 - 45 - 67 + 89
:max_solutions("46" => $["9", "-9"])
:first_unsolvable(211)
:two_largest_sums(["123456789", "23456790"])
Python
<lang python> from itertools import product, islice
def expr(p):
return "{}1{}2{}3{}4{}5{}6{}7{}8{}9".format(*p)
def gen_expr():
op = ['+', '-', ] return [expr(p) for p in product(op, repeat=9) if p[0] != '+']
def all_exprs():
values = {}
for expr in gen_expr():
val = eval(expr)
if val not in values:
values[val] = 1
else:
values[val] += 1
return values
def sum_to(val):
for s in filter(lambda x: x[0] == val, map(lambda x: (eval(x), x), gen_expr())):
print(s)
def max_solve():
print("Sum {} has the maximum number of solutions: {}".
format(*max(all_exprs().items(), key=lambda x: x[1])))
def min_solve():
values = all_exprs()
for i in range(123456789):
if i not in values:
print("Lowest positive sum that can't be expressed: {}".format(i))
return
def highest_sums(n=10):
sums = map(lambda x: x[0],
islice(sorted(all_exprs().items(), key=lambda x: x[0], reverse=True), n))
print("Highest Sums: {}".format(list(sums)))
sum_to(100)
max_solve()
min_solve()
highest_sums()
</lang>
REXX
<lang rexx>/*REXX pgm solves a puzzle: using the string 123456789, insert - or + to sum to 100*/ parse arg LO HI . /*obtain optional arguments from the CL*/ if LO== | LO=="," then LO=100 /*Not specified? Then use the default.*/ if HI== | HI=="," then HI=LO /* " " " " " " */ if LO==00 then HI=123456789 /*LOW specified as zero with leading 0.*/ ops= '+-'; L=length(ops) + 1 /*define operators (and their length). */ @.=; do i=1 to L-1; @.i=substr(ops,i,1) /* " some handy-dandy REXX literals*/
end /*i*/ /* " individual operators for speed*/
mx=0; mn=999999 /*initialize the minimums and maximums.*/ mxL=; mnL=; do j=LO to HI until LO==00 & mn==0 /*solve with a range of sums*/
z=solve(j) /*find # of solutions for J.*/
if z> mx then mxL= /*see if this is a new max. */
if z>=mx then do; mxL=mxL j; mx=z; end /*remember this new maximum.*/
if z< mn then mnL= /*see if this is a new min. */
if z<=mn then do; mnL=mnL j; mn=z; end /*remember this new minimum.*/
end /*j*/
if LO==HI then exit /*don't display max & min ? */ @@= 'number of solutions: '; say _=words(mxL); say 'sum's(_) "of" mxL ' 's(_,"have",'has') 'the maximum' @@ mx _=words(mnL); say 'sum's(_) "of" mnL ' 's(_,"have",'has') 'the minimum' @@ mn exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ s: if arg(1)==1 then return arg(3); return word(arg(2) "s",1) /*simple pluralizer*/ /*──────────────────────────────────────────────────────────────────────────────────────*/ solve: parse arg answer; # =0 /*obtain the answer (sum) to the puzzle*/
do a=L-1 to L; aa= @.a'1' /*choose one of ─ or nothing. */
do b=1 for L; bb=aa || @.b'2' /* " " " ─ +, or abutment.*/
do c=1 for L; cc=bb || @.c'3' /* " " " " " " " */
do d=1 for L; dd=cc || @.d'4' /* " " " " " " " */
do e=1 for L; ee=dd || @.e'5' /* " " " " " " " */
do f=1 for L; ff=ee || @.f'6' /* " " " " " " " */
do g=1 for L; gg=ff || @.g'7' /* " " " " " " " */
do h=1 for L; hh=gg || @.h'8' /* " " " " " " " */
do i=1 for L; ii=hh || @.i'9' /* " " " " " " " */
interpret '$=' ii /*calculate the sum of modified string.*/
if $\==answer then iterate /*Is sum not equal to answer? Then skip*/
#=#+1; if LO==HI then say 'solution: ' $ " ◄───► " ii
end /*i*/
end /*h*/
end /*g*/
end /*f*/
end /*e*/
end /*d*/
end /*c*/
end /*b*/
end /*a*/
y=# /* [↓] adjust the number of solutions?*/
if y==0 then y='no' /* [↓] left justify plural of solution*/
if LO\==00 then say right(y, 9) 'solution's(#, , " ") 'found for' ,
right(j, length(HI) ) left(, #, "─")
return # /*return the number of solutions found.*/</lang>
output when the default input is used:
solution: 100 ◄───► -1+2-3+4+5+6+78+9
solution: 100 ◄───► 1+2+3-4+5+6+78+9
solution: 100 ◄───► 1+2+34-5+67-8+9
solution: 100 ◄───► 1+23-4+5+6+78-9
solution: 100 ◄───► 1+23-4+56+7+8+9
solution: 100 ◄───► 12+3+4+5-6-7+89
solution: 100 ◄───► 12+3-4+5+67+8+9
solution: 100 ◄───► 12-3-4+5-6+7+89
solution: 100 ◄───► 123+4-5+67-89
solution: 100 ◄───► 123+45-67+8-9
solution: 100 ◄───► 123-4-5-6-7+8-9
solution: 100 ◄───► 123-45-67+89
12 solutions found for 100
output when the following input is used: 00
sum of 9 has the maximum number of solutions: 46 sum of 211 has the minimum number of solutions: 0
Ruby
<lang ruby>def gen_expr
x = ['-', ]
y = ['+', '-', ]
x.product(y,y,y,y,y,y,y,y)
.map do |a,b,c,d,e,f,g,h,i|
"#{a}1#{b}2#{c}3#{d}4#{e}5#{f}6#{g}7#{h}8#{i}9"
end
end
def sum_to(val)
gen_expr.map{|expr| [eval(expr), expr]}.select{|v,expr| v==val}.each{|x| p x}
end
def max_solve
n,size = gen_expr.group_by{|expr| eval(expr)}
.select{|val,_| val>=0}
.map{|val,exprs| [val, exprs.size]}
.max_by{|_,size| size}
puts "sum of #{n} has the maximum number of solutions : #{size}"
end
def min_solve
solves = gen_expr.group_by{|expr| eval(expr)}
n = 0.step{|i| break i unless solves[i]}
puts "lowest positive sum that can't be expressed : #{n}"
end
def highest_sums(n=10)
n = gen_expr.map{|expr| eval(expr)}.uniq.sort.reverse.take(n)
puts "highest sums : #{n}"
end
sum_to(100) max_solve min_solve highest_sums</lang>
- Output:
[100, "-1+2-3+4+5+6+78+9"] [100, "1+2+3-4+5+6+78+9"] [100, "1+2+34-5+67-8+9"] [100, "1+23-4+5+6+78-9"] [100, "1+23-4+56+7+8+9"] [100, "12+3+4+5-6-7+89"] [100, "12+3-4+5+67+8+9"] [100, "12-3-4+5-6+7+89"] [100, "123+4-5+67-89"] [100, "123+45-67+8-9"] [100, "123-4-5-6-7+8-9"] [100, "123-45-67+89"] sum of 9 has the maximum number of solutions : 46 lowest positive sum that can't be expressed : 211 highest sums : [123456789, 23456790, 23456788, 12345687, 12345669, 3456801, 3456792, 3456790, 3456788, 3456786]
zkl
Taking a big clue from Haskell and just calculate the world. <lang zkl>var all = // ( (1,12,123...-1,-12,...), (2,23,...) ...)
(9).pump(List,fcn(n){ split("123456789"[n,*]) }) // 45
.apply(fcn(ns){ ns.extend(ns.copy().apply('*(-1))) }); // 90
fcn calcAllSums{ // calculate all 6572 sums (1715 unique)
fcn(n,sum,soFar,r){
if(n==9) return();
foreach b in (all[n]){
if(sum+b>=0 and b.abs()%10==9) r.appendV(sum+b,"%s%+d".fmt(soFar,b)); self.fcn(b.abs()%10,sum + b,"%s%+d".fmt(soFar,b),r);
} }(0,0,"",r:=Dictionary()); r
}
// "123" --> (1,12,123)
fcn split(nstr){ (1).pump(nstr.len(),List,nstr.get.fp(0),"toInt") }</lang> <lang zkl>fcn showSums(allSums,N=100,printSolutions=2){
slns:=allSums.find(N,T);
if(printSolutions) println("%d solutions for N=%d".fmt(slns.len(),N));
if(printSolutions==2) println(slns.concat("\n"));
println();
}
allSums:=calcAllSums(); showSums(allSums); showSums(allSums,0,1);
println("Smallest postive integer with no solution: ",
[1..].filter1('wrap(n){ Void==allSums.find(n) }));
println("5 commonest sums (sum, number of ways to calculate to it):"); ms:=allSums.values.apply("len").sort()[-5,*]; // 5 mostest sums allSums.pump(List, // get those pairs
'wrap([(k,v)]){ v=v.len(); ms.holds(v) and T(k.toInt(),v) or Void.Skip })
.sort(fcn(kv1,kv2){ kv1[1]>kv2[1] }) // and sort .println();</lang>
- Output:
12 solutions for N=100 +1+2+3-4+5+6+78+9 +1+2+34-5+67-8+9 +1+23-4+5+6+78-9 +1+23-4+56+7+8+9 +12+3+4+5-6-7+89 +12+3-4+5+67+8+9 +12-3-4+5-6+7+89 +123+4-5+67-89 +123+45-67+8-9 +123-4-5-6-7+8-9 +123-45-67+89 -1+2-3+4+5+6+78+9 22 solutions for N=0 Smallest postive integer with no solution: 211 5 commonest sums (sum, number of ways to calculate to it): L(L(9,46),L(27,44),L(15,43),L(1,43),L(21,43))