Two bullet roulette: Difference between revisions
m (→{{header|REXX}}: optimized execution which yields around 30% speed improvement.) |
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Youtube video on the Russian 1895 Nagant revolver [[https://www.youtube.com/watch?v=Dh1mojMaEtM]] |
Youtube video on the Russian 1895 Nagant revolver [[https://www.youtube.com/watch?v=Dh1mojMaEtM]] |
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<br><br> |
<br><br> |
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=={{header|11l}}== |
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{{trans|Go}} |
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<lang 11l>UInt32 seed = 0 |
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F nonrandom(n) |
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:seed = 1664525 * :seed + 1013904223 |
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R Int(:seed >> 16) % n |
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V cylinder = [0B] * 6 |
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F rshift() |
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V t = :cylinder[5] |
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L(i) (4..0).step(-1) |
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:cylinder[i + 1] = :cylinder[i] |
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:cylinder[0] = t |
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F unload() |
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L(i) 6 |
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:cylinder[i] = 0B |
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F load() |
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L :cylinder[0] |
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rshift() |
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:cylinder[0] = 1B |
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rshift() |
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F spin() |
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L(i) 1 .. nonrandom(6) |
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rshift() |
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F fire() |
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V shot = :cylinder[0] |
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rshift() |
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R shot |
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F method(s) |
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unload() |
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L(c) s |
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S c |
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‘L’ |
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load() |
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‘S’ |
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spin() |
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‘F’ |
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I fire() |
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R 1 |
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R 0 |
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F mstring(s) |
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[String] l |
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L(c) s |
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S c |
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‘L’ |
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l [+]= ‘load’ |
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‘S’ |
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l [+]= ‘spin’ |
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‘F’ |
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l [+]= ‘fire’ |
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R l.join(‘, ’) |
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V tests = 100000 |
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L(m) [‘LSLSFSF’, ‘LSLSFF’, ‘LLSFSF’, ‘LLSFF’] |
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V sum = 0 |
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L 0 .< tests |
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sum += method(m) |
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V pc = Float(sum) * 100 / tests |
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print(‘#<40 produces #2.3% deaths.’.format(mstring(m), pc))</lang> |
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{{out}} |
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<pre> |
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load, spin, load, spin, fire, spin, fire produces 55.434% deaths. |
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load, spin, load, spin, fire, fire produces 58.373% deaths. |
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load, load, spin, fire, spin, fire produces 55.428% deaths. |
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load, load, spin, fire, fire produces 50.041% deaths. |
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</pre> |
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=={{header|C}}== |
=={{header|C}}== |
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Revision as of 02:25, 18 July 2021
The following is supposedly a question given to mathematics graduates seeking jobs on Wall Street:
A revolver handgun has a revolving cylinder with six chambers for bullets.
It is loaded with the following procedure:
1. Check the first chamber to the right of the trigger for a bullet. If a bullet
is seen, the cylinder is rotated one chamber clockwise and the next chamber
checked until an empty chamber is found.
2. A cartridge containing a bullet is placed in the empty chamber.
3. The cylinder is then rotated one chamber clockwise.
To randomize the cylinder's position, the cylinder is spun, which causes the cylinder to take
a random position from 1 to 6 chamber rotations clockwise from its starting position.
When the trigger is pulled the gun will fire if there is a bullet in position 0, which is just
counterclockwise from the loading position.
The gun is unloaded by removing all cartridges from the cylinder.
According to the legend, a suicidal Russian imperial military officer plays a game of Russian
roulette by putting two bullets in a six-chamber cylinder and pulls the trigger twice.
If the gun fires with a trigger pull, this is considered a successful suicide.
The cylinder is always spun before the first shot, but it may or may not be spun after putting
in the first bullet and may or may not be spun after taking the first shot.
Which of the following situations produces the highest probability of suicide?
A. Spinning the cylinder after loading the first bullet, and spinning again after the first shot.
B. Spinning the cylinder after loading the first bullet only.
C. Spinning the cylinder after firing the first shot only.
D. Not spinning the cylinder either after loading the first bullet or after the first shot.
E. The probability is the same for all cases.
- Task
- Run a repeated simulation of each of the above scenario, calculating the percentage of suicide with a randomization of the four spinning, loading and firing order scenarios.
- Show the results as a percentage of deaths for each type of scenario.
- The hand calculated probabilities are 5/9, 7/12, 5/9, and 1/2. A correct program should produce results close enough to those to allow a correct response to the interview question.
- Reference
Youtube video on the Russian 1895 Nagant revolver [[1]]
11l
<lang 11l>UInt32 seed = 0 F nonrandom(n)
:seed = 1664525 * :seed + 1013904223 R Int(:seed >> 16) % n
V cylinder = [0B] * 6
F rshift()
V t = :cylinder[5]
L(i) (4..0).step(-1)
:cylinder[i + 1] = :cylinder[i]
:cylinder[0] = t
F unload()
L(i) 6
:cylinder[i] = 0B
F load()
L :cylinder[0]
rshift()
:cylinder[0] = 1B
rshift()
F spin()
L(i) 1 .. nonrandom(6)
rshift()
F fire()
V shot = :cylinder[0] rshift() R shot
F method(s)
unload()
L(c) s
S c
‘L’
load()
‘S’
spin()
‘F’
I fire()
R 1
R 0
F mstring(s)
[String] l
L(c) s
S c
‘L’
l [+]= ‘load’
‘S’
l [+]= ‘spin’
‘F’
l [+]= ‘fire’
R l.join(‘, ’)
V tests = 100000 L(m) [‘LSLSFSF’, ‘LSLSFF’, ‘LLSFSF’, ‘LLSFF’]
V sum = 0
L 0 .< tests
sum += method(m)
V pc = Float(sum) * 100 / tests
print(‘#<40 produces #2.3% deaths.’.format(mstring(m), pc))</lang>
- Output:
load, spin, load, spin, fire, spin, fire produces 55.434% deaths. load, spin, load, spin, fire, fire produces 58.373% deaths. load, load, spin, fire, spin, fire produces 55.428% deaths. load, load, spin, fire, fire produces 50.041% deaths.
C
<lang c>#include <stdbool.h>
- include <stdio.h>
- include <stdlib.h>
- include <string.h>
- include <time.h>
static int nextInt(int size) {
return rand() % size;
}
static bool cylinder[6];
static void rshift() {
bool t = cylinder[5];
int i;
for (i = 4; i >= 0; i--) {
cylinder[i + 1] = cylinder[i];
}
cylinder[0] = t;
}
static void unload() {
int i;
for (i = 0; i < 6; i++) {
cylinder[i] = false;
}
}
static void load() {
while (cylinder[0]) {
rshift();
}
cylinder[0] = true;
rshift();
}
static void spin() {
int lim = nextInt(6) + 1;
int i;
for (i = 1; i < lim; i++) {
rshift();
}
}
static bool fire() {
bool shot = cylinder[0]; rshift(); return shot;
}
static int method(const char *s) {
unload();
for (; *s != '\0'; s++) {
switch (*s) {
case 'L':
load();
break;
case 'S':
spin();
break;
case 'F':
if (fire()) {
return 1;
}
break;
}
}
return 0;
}
static void append(char *out, const char *txt) {
if (*out != '\0') {
strcat(out, ", ");
}
strcat(out, txt);
}
static void mstring(const char *s, char *out) {
for (; *s != '\0'; s++) {
switch (*s) {
case 'L':
append(out, "load");
break;
case 'S':
append(out, "spin");
break;
case 'F':
append(out, "fire");
break;
}
}
}
static void test(char *src) {
char buffer[41] = ""; const int tests = 100000; int sum = 0; int t; double pc;
for (t = 0; t < tests; t++) {
sum += method(src);
}
mstring(src, buffer); pc = 100.0 * sum / tests;
printf("%-40s produces %6.3f%% deaths.\n", buffer, pc);
}
int main() {
srand(time(0));
test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");
return 0;
}</lang>
- Output:
load, spin, load, spin, fire, spin, fire produces 55.456% deaths. load, spin, load, spin, fire, fire produces 58.301% deaths. load, load, spin, fire, spin, fire produces 55.487% deaths. load, load, spin, fire, fire produces 50.289% deaths.
C++
<lang cpp>#include <array>
- include <iomanip>
- include <iostream>
- include <random>
- include <sstream>
class Roulette { private:
std::array<bool, 6> cylinder;
std::mt19937 gen; std::uniform_int_distribution<> distrib;
int next_int() {
return distrib(gen);
}
void rshift() {
std::rotate(cylinder.begin(), cylinder.begin() + 1, cylinder.end());
}
void unload() {
std::fill(cylinder.begin(), cylinder.end(), false);
}
void load() {
while (cylinder[0]) {
rshift();
}
cylinder[0] = true;
rshift();
}
void spin() {
int lim = next_int();
for (int i = 1; i < lim; i++) {
rshift();
}
}
bool fire() {
auto shot = cylinder[0];
rshift();
return shot;
}
public:
Roulette() {
std::random_device rd;
gen = std::mt19937(rd());
distrib = std::uniform_int_distribution<>(1, 6);
unload(); }
int method(const std::string &s) {
unload();
for (auto c : s) {
switch (c) {
case 'L':
load();
break;
case 'S':
spin();
break;
case 'F':
if (fire()) {
return 1;
}
break;
}
}
return 0;
}
};
std::string mstring(const std::string &s) {
std::stringstream ss; bool first = true;
auto append = [&ss, &first](const std::string s) {
if (first) {
first = false;
} else {
ss << ", ";
}
ss << s;
};
for (auto c : s) {
switch (c) {
case 'L':
append("load");
break;
case 'S':
append("spin");
break;
case 'F':
append("fire");
break;
}
}
return ss.str();
}
void test(const std::string &src) {
const int tests = 100000; int sum = 0;
Roulette r;
for (int t = 0; t < tests; t++) {
sum += r.method(src);
}
double pc = 100.0 * sum / tests;
std::cout << std::left << std::setw(40) << mstring(src) << " produces " << pc << "% deaths.\n";
}
int main() {
test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");
return 0;
}</lang>
- Output:
load, spin, load, spin, fire, spin, fire produces 55.487% deaths. load, spin, load, spin, fire, fire produces 58.542% deaths. load, load, spin, fire, spin, fire produces 55.675% deaths. load, load, spin, fire, fire produces 50.051% deaths.
Factor
<lang factor>USING: accessors assocs circular formatting fry kernel literals math random sequences ; IN: rosetta-code.roulette
CONSTANT: cyl $[ { f f f f f f } <circular> ]
- cylinder ( -- seq ) cyl [ drop f ] map! ;
- load ( seq -- seq' )
0 over nth [ dup rotate-circular ] when t 0 rot [ set-nth ] [ rotate-circular ] [ ] tri ;
- spin ( seq -- seq' ) [ 6 random 1 + + ] change-start ;
- fire ( seq -- ? seq' )
[ 0 swap nth ] [ rotate-circular ] [ ] tri ;
- LSLSFSF ( -- ? ) cylinder load spin load spin fire spin fire drop or ;
- LSLSFF ( -- ? ) cylinder load spin load spin fire fire drop or ;
- LLSFSF ( -- ? ) cylinder load load spin fire spin fire drop or ;
- LLSFF ( -- ? ) cylinder load load spin fire fire drop or ;
- percent ( ... n quot: ( ... -- ... ? ) -- ... x )
0 -rot '[ _ call( -- ? ) 1 0 ? + ] [ times ] keepd /f 100 * ; inline
- run-test ( description quot -- )
100,000 swap percent "Method <%s> produces %.3f%% deaths.\n" printf ;
- main ( -- )
{
{ "load, spin, load, spin, fire, spin, fire" [ LSLSFSF ] }
{ "load, spin, load, spin, fire, fire" [ LSLSFF ] }
{ "load, load, spin, fire, spin, fire" [ LLSFSF ] }
{ "load, load, spin, fire, fire" [ LLSFF ] }
} [ run-test ] assoc-each ;
MAIN: main</lang>
- Output:
"rosetta-code.roulette" run
Method <load, spin, load, spin, fire, spin, fire> produces 55.598% deaths. Method <load, spin, load, spin, fire, fire> produces 58.390% deaths. Method <load, load, spin, fire, spin, fire> produces 55.500% deaths. Method <load, load, spin, fire, fire> produces 49.841% deaths.
Go
Though procedural rather than OO. <lang go>package main
import (
"fmt" "math/rand" "strings" "time"
)
var cylinder = [6]bool{}
func rshift() {
t := cylinder[5]
for i := 4; i >= 0; i-- {
cylinder[i+1] = cylinder[i]
}
cylinder[0] = t
}
func unload() {
for i := 0; i < 6; i++ {
cylinder[i] = false
}
}
func load() {
for cylinder[0] {
rshift()
}
cylinder[0] = true
rshift()
}
func spin() {
var lim = 1 + rand.Intn(6)
for i := 1; i < lim; i++ {
rshift()
}
}
func fire() bool {
shot := cylinder[0] rshift() return shot
}
func method(s string) int {
unload()
for _, c := range s {
switch c {
case 'L':
load()
case 'S':
spin()
case 'F':
if fire() {
return 1
}
}
}
return 0
}
func mstring(s string) string {
var l []string
for _, c := range s {
switch c {
case 'L':
l = append(l, "load")
case 'S':
l = append(l, "spin")
case 'F':
l = append(l, "fire")
}
}
return strings.Join(l, ", ")
}
func main() {
rand.Seed(time.Now().UnixNano())
tests := 100000
for _, m := range []string{"LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"} {
sum := 0
for t := 1; t <= tests; t++ {
sum += method(m)
}
pc := float64(sum) * 100 / float64(tests)
fmt.Printf("%-40s produces %6.3f%% deaths.\n", mstring(m), pc)
}
}</lang>
- Output:
Sample run:
load, spin, load, spin, fire, spin, fire produces 55.267% deaths. load, spin, load, spin, fire, fire produces 58.110% deaths. load, load, spin, fire, spin, fire produces 55.405% deaths. load, load, spin, fire, fire produces 49.889% deaths.
Julia
<lang julia>const cyl = zeros(Bool, 6)
function load()
while cyl[1]
cyl .= circshift(cyl, 1)
end
cyl[1] = true
cyl .= circshift(cyl, 1)
end
spin() = (cyl .= circshift(cyl, rand(1:6)))
fire() = (shot = cyl[1]; cyl .= circshift(cyl, 1); shot)
function LSLSFSF()
cyl .= 0 load(); spin(); load(); spin() fire() && return true spin(); return fire()
end
function LSLSFF()
cyl .= 0 load(); spin(); load(); spin() fire() && return true return fire()
end
function LLSFSF()
cyl .= 0 load(); load(); spin() fire() && return true spin(); return fire()
end
function LLSFF()
cyl .= 0 load(); load(); spin() fire() && return true return fire()
end
function testmethods(N = 10000000)
for (name, method) in [("load, spin, load, spin, fire, spin, fire", LSLSFSF),
("load, spin, load, spin, fire, fire", LSLSFF),
("load, load, spin, fire, spin, fire", LLSFSF),
("load, load, spin, fire, fire", LLSFF)]
percentage = 100 * sum([method() for _ in 1:N]) / N
println("Method $name produces $percentage per cent deaths.")
end
end
testmethods()
</lang>
- Output:
Method load, spin, load, spin, fire, spin, fire produces 55.54253 per cent deaths. Method load, spin, load, spin, fire, fire produces 58.32598 per cent deaths. Method load, load, spin, fire, spin, fire produces 55.54244 per cent deaths. Method load, load, spin, fire, fire produces 50.02247 per cent deaths.
Kotlin
<lang scala>import kotlin.random.Random
val cylinder = Array(6) { false }
fun rShift() {
val t = cylinder[cylinder.size - 1]
for (i in (0 until cylinder.size - 1).reversed()) {
cylinder[i + 1] = cylinder[i]
}
cylinder[0] = t
}
fun unload() {
for (i in cylinder.indices) {
cylinder[i] = false
}
}
fun load() {
while (cylinder[0]) {
rShift()
}
cylinder[0] = true
rShift()
}
fun spin() {
val lim = Random.nextInt(0, 6) + 1
for (i in 1..lim) {
rShift()
}
}
fun fire(): Boolean {
val shot = cylinder[0] rShift() return shot
}
fun method(s: String): Int {
unload()
for (c in s) {
when (c) {
'L' -> {
load()
}
'S' -> {
spin()
}
'F' -> {
if (fire()) {
return 1
}
}
}
}
return 0
}
fun mString(s: String): String {
val buf = StringBuilder()
fun append(txt: String) {
if (buf.isNotEmpty()) {
buf.append(", ")
}
buf.append(txt)
}
for (c in s) {
when (c) {
'L' -> {
append("load")
}
'S' -> {
append("spin")
}
'F' -> {
append("fire")
}
}
}
return buf.toString()
}
fun test(src: String) {
val tests = 100000 var sum = 0
for (t in 0..tests) {
sum += method(src)
}
val str = mString(src)
val pc = 100.0 * sum / tests
println("%-40s produces %6.3f%% deaths.".format(str, pc))
}
fun main() {
test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");
}</lang>
- Output:
load, spin, load, spin, fire, spin, fire produces 55.638% deaths. load, spin, load, spin, fire, fire produces 58.140% deaths. load, load, spin, fire, spin, fire produces 55.725% deaths. load, load, spin, fire, fire produces 49.875% deaths.
Nim
<lang Nim>import algorithm, random, sequtils, strformat, strutils, tables
type
Revolver = array[6, bool]
Action {.pure.} = enum Load, Spin, Fire, Error
const Actions = {'L': Load, 'S': Spin, 'F': Fire}.toTable
func spin(revolver: var Revolver; count: Positive) =
revolver.rotateLeft(-count)
func load(revolver: var Revolver) =
while revolver[1]: revolver.spin(1) revolver[1] = true revolver.spin(1)
func fire(revolver: var Revolver): bool =
result = revolver[0] revolver.spin(1)
proc test(scenario: string) =
let actions = scenario.mapIt(Actions.getOrDefault(it, Error))
var deaths = 0
var count = 100_000
for _ in 1..count:
var revolver: Revolver
for action in actions:
case action
of Load:
revolver.load()
of Spin:
revolver.spin(rand(1..6))
of Fire:
if revolver.fire():
inc deaths
break
of Error:
raise newException(ValueError, "encountered an unknown action.")
echo &"""{100 * deaths / count:5.2f}% deaths for scenario {actions.join(", ")}."""
randomize() for scenario in ["LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"]:
test(scenario)</lang>
- Output:
55.73% deaths for scenario Load, Spin, Load, Spin, Fire, Spin, Fire. 58.09% deaths for scenario Load, Spin, Load, Spin, Fire, Fire. 55.74% deaths for scenario Load, Load, Spin, Fire, Spin, Fire. 50.14% deaths for scenario Load, Load, Spin, Fire, Fire.
Perl
<lang perl>use strict; use warnings; use feature 'say';
my @cyl; my $shots = 6;
sub load {
push @cyl, shift @cyl while $cyl[1]; $cyl[1] = 1; push @cyl, shift @cyl
}
sub spin { push @cyl, shift @cyl for 0 .. int rand @cyl } sub fire { push @cyl, shift @cyl; $cyl[0] }
sub LSLSFSF {
@cyl = (0) x $shots; load, spin, load, spin; return 1 if fire; spin; fire
}
sub LSLSFF {
@cyl = (0) x $shots; load, spin, load, spin; fire or fire
}
sub LLSFSF {
@cyl = (0) x $shots; load, load, spin; return 1 if fire; spin; fire
}
sub LLSFF {
@cyl = (0) x $shots; load, load, spin; fire or fire
}
my $trials = 10000;
for my $ref (<LSLSFSF LSLSFF LLSFSF LLSFF>) {
no strict 'refs'; my $total = 0; $total += &$ref for 1..$trials; printf "%7s %.2f%%\n", $ref, $total / $trials * 100;
}</lang>
- Output:
LSLSFSF 55.04% LSLSFF 58.77% LLSFSF 55.09% LLSFF 50.13%
Phix
<lang Phix>function spin(sequence revolver, integer count)
while count do
revolver = revolver[$]&revolver[1..$-1]
count -= 1
end while
return revolver
end function
function load(sequence revolver)
while revolver[1] do
revolver = spin(revolver,1)
end while
revolver[1] = true
revolver = spin(revolver,1)
return revolver
end function
bool dead = false function fire(sequence revolver)
if revolver[1] then dead = true end if revolver = spin(revolver,1) return revolver
end function
procedure test(string method)
integer deaths = 0,
limit = 100000
for n=1 to limit do
sequence revolver = repeat(false,6)
dead = false
for i=1 to length(method) do
integer ch = method[i]
switch ch
case 'L': revolver = load(revolver)
case 'S': revolver = spin(revolver,rand(6))
case 'F': revolver = fire(revolver)
end switch
end for
deaths += dead
end for
printf(1,"%s: %5.2f\n",{method,100*deaths/limit})
end procedure
printf(1,"Load/Spin/Fire method percentage fatalities:\n") papply({"LSLSFSF","LSLSFF","LLSFSF","LLSFF"},test)</lang>
- Output:
Load/Spin/Fire method percentage fatalities: LSLSFSF: 55.66 LSLSFF: 58.55 LLSFSF: 55.76 LLSFF: 49.97
Python
<lang python>""" Russian roulette problem """ import numpy as np
class Revolver:
""" simulates 6-shot revolving cylinger pistol """
def __init__(self):
""" start unloaded """
self.cylinder = np.array([False] * 6)
def unload(self):
""" empty all chambers of cylinder """
self.cylinder[:] = False
def load(self):
""" load a chamber (advance til empty if full already), then advance once """
while self.cylinder[1]:
self.cylinder[:] = np.roll(self.cylinder, 1)
self.cylinder[1] = True
def spin(self):
""" spin cylinder, randomizing position of chamber to be fired """
self.cylinder[:] = np.roll(self.cylinder, np.random.randint(1, high=7))
def fire(self):
""" pull trigger of revolver, return True if fired, False if did not fire """
shot = self.cylinder[0]
self.cylinder[:] = np.roll(self.cylinder, 1)
return shot
def LSLSFSF(self):
""" load, spin, load, spin, fire, spin, fire """
self.unload()
self.load()
self.spin()
self.load()
self.spin()
if self.fire():
return True
self.spin()
if self.fire():
return True
return False
def LSLSFF(self):
""" load, spin, load, spin, fire, fire """
self.unload()
self.load()
self.spin()
self.load()
self.spin()
if self.fire():
return True
if self.fire():
return True
return False
def LLSFSF(self):
""" load, load, spin, fire, spin, fire """
self.unload()
self.load()
self.load()
self.spin()
if self.fire():
return True
self.spin()
if self.fire():
return True
return False
def LLSFF(self):
""" load, load, spin, fire, fire """
self.unload()
self.load()
self.load()
self.spin()
if self.fire():
return True
if self.fire():
return True
return False
if __name__ == '__main__':
REV = Revolver()
TESTCOUNT = 100000
for (name, method) in [['load, spin, load, spin, fire, spin, fire', REV.LSLSFSF],
['load, spin, load, spin, fire, fire', REV.LSLSFF],
['load, load, spin, fire, spin, fire', REV.LLSFSF],
['load, load, spin, fire, fire', REV.LLSFF]]:
percentage = 100 * sum([method() for _ in range(TESTCOUNT)]) / TESTCOUNT
print("Method", name, "produces", percentage, "per cent deaths.")
</lang>
- Output:
Method load, spin, load, spin, fire, spin, fire produces 55.652 per cent deaths. Method load, spin, load, spin, fire, fire produces 58.239 per cent deaths. Method load, load, spin, fire, spin, fire produces 55.774 per cent deaths. Method load, load, spin, fire, fire produces 50.071 per cent deaths.
Raku
<lang perl6>unit sub MAIN ($shots = 6);
my @cyl;
sub load () {
@cyl.=rotate(-1) while @cyl[1]; @cyl[1] = 1; @cyl.=rotate(-1);
}
sub spin () { @cyl.=rotate: (^@cyl).pick }
sub fire () { @cyl.=rotate; @cyl[0] }
sub LSLSFSF {
@cyl = 0 xx $shots; load, spin, load, spin; return 1 if fire; spin; fire
}
sub LSLSFF {
@cyl = 0 xx $shots; load, spin, load, spin; fire() || fire
}
sub LLSFSF {
@cyl = 0 xx $shots; load, load, spin; return 1 if fire; spin; fire
}
sub LLSFF {
@cyl = 0 xx $shots; load, load, spin; fire() || fire
}
my %revolver; my $trials = 100000;
for ^$trials {
%revolver<LSLSFSF> += LSLSFSF; %revolver<LSLSFF> += LSLSFF; %revolver<LLSFSF> += LLSFSF; %revolver<LLSFF> += LLSFF;
}
say "{.fmt('%7s')}: %{(%revolver{$_} / $trials × 100).fmt('%.2f')}"
for <LSLSFSF LSLSFF LLSFSF LLSFF></lang>
- Sample output (default; 6 shooter):
LSLSFSF: %55.37 LSLSFF: %58.30 LLSFSF: %55.42 LLSFF: %50.29
Though if you go and look at the Wikipedia article for the 1895 Nagant revolver mentioned in the task reference section, you'll see it is actually a 7 shot revolver... so, run again with 7 chambers:
raku roulette.raku 7
- Sample output (7 shooter):
LSLSFSF: %49.29 LSLSFF: %51.14 LLSFSF: %48.74 LLSFF: %43.08
Or, how about a Ruger GP100 10 round revolver?
raku roulette.raku 10
- Sample output (10 shooter):
LSLSFSF: %36.00 LSLSFF: %37.00 LLSFSF: %36.13 LLSFF: %29.77
Doesn't change the answers, B (LSLSFF) is definitely the worst most likely choice in all cases.
REXX
This REXX version eliminates the spinning of the bullet chamber if the random number for a spin is 6 (which would
normally just spin the bullet chamber around to its initial position, thereby saving some busywork by the program).
Changing the cartridge chamber from an index array to a simple string made the program around 200% faster. <lang rexx>/*REXX pgm simulates scenarios for a two─bullet Russian roulette game with a 6 cyl. gun.*/ parse arg cyls tests seed . /*obtain optional arguments from the CL*/ if cyls== | cyls=="," then cyls= 6 /*Not specified? Then use the default.*/ if tests== | tests=="," then tests= 100000 /* " " " " " " */ if datatype(seed, 'W') then call random ,,seed /* " " " " " " */ cyls_ = cyls - 1; @0= copies(0, cyls) /*shortcut placeholder for cylinders-1 */ @abc= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' /*indices for the various options used.*/ scenarios= 'LSLSFsF LSLSFF LLSFSF LLSFF' /*the list of scenarios to be tested. */
- = words(scenarios) /*the number of actions in a scenario. */
/*The scenarios are case insensitive. */
do m=1 for #; q= word(scenarios, m) /*test each of the scenarios specified.*/
sum= 0 /*initialize the sum to zero. */
do tests; sum= sum + method() /*added the sums up for the percentages*/
end /*tests*/
pc= left( (sum * 100 / tests)"%", 7)
say act() ' (option' substr(@abc, m, 1)") produces " pc ' deaths.'
end /*m*/
exit 0 /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ fire: != left(@, 1); @= right(@, cyls_)left(@, 1); /* ◄──── next cyl.*/ return ! load: if left(@, 1) then @= right(@, cyls_)left(@, 1); @= 1||right(@, cyls_); return spin: ?= random(1, cyls); if ?\==cyls then @= substr(@ || @, ? + 1, cyls); return /*──────────────────────────────────────────────────────────────────────────────────────*/ method: @= @0; do a=1 for length(q); y= substr(q, a, 1)
if y=='L' then call load
else if y=='S' then call spin
else if y=='F' then if fire() then return 1
end /*a*/; return 0
/*──────────────────────────────────────────────────────────────────────────────────────*/ act: $=; do a=1 for length(q); y= substr(q, a, 1)
if y=='L' then $= $", load"
if y=='S' then $= $", spin"
if y=='F' then $= $", fire"
end /*a*/; return right( strip( strip($, , ",") ), 45)</lang>
- output when using the default inputs, showing that 2nd option B has the highest probability for a suicide:
load, spin, load, spin, fire, spin, fire (option A) produces 55.44% deaths.
load, spin, load, spin, fire, fire (option B) produces 58.487% deaths.
load, load, spin, fire, spin, fire (option C) produces 55.82% deaths.
load, load, spin, fire, fire (option D) produces 50.021% deaths.
Wren
<lang ecmascript>import "random" for Random import "/fmt" for Fmt
var Rand = Random.new()
class Revolver {
construct new() {
_cylinder = List.filled(6, false)
}
rshift() {
var t = _cylinder[-1]
for (i in 4..0) _cylinder[i+1] = _cylinder[i]
_cylinder[0] = t
}
unload() {
for (i in 0..5) _cylinder[i] = false
}
load() {
while (_cylinder[0]) rshift()
_cylinder[0] = true
rshift()
}
spin() {
for (i in 1..Rand.int(1, 7)) rshift()
}
fire() {
var shot = _cylinder[0]
rshift()
return shot
}
method(s) {
unload()
for (c in s) {
if (c == "L") {
load()
} else if (c == "S") {
spin()
} else if (c == "F") {
if (fire()) return 1
}
}
return 0
}
static mstring(s) {
var l = []
for (c in s) {
if (c == "L") {
l.add("load")
} else if (c == "S") {
l.add("spin")
} else if (c == "F") {
l.add("fire")
}
}
return l.join(", ")
}
}
var rev = Revolver.new() var tests = 100000 for (m in ["LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"]) {
var sum = 0
for (t in 1..tests) sum = sum + rev.method(m)
Fmt.print("$-40s produces $6.3f\% deaths.", Revolver.mstring(m), sum * 100 / tests)
}</lang>
- Output:
Sample run:
load, spin, load, spin, fire, spin, fire produces 55.500% deaths. load, spin, load, spin, fire, fire produces 58.162% deaths. load, load, spin, fire, spin, fire produces 55.512% deaths. load, load, spin, fire, fire produces 50.013% deaths.