Find minimum number of coins that make a given value

Task: Find minimum number of coins that make a given value

coins = [1,2,5,10,20,50,100,200]
value = 988

Coins are:
4*200
1*100
1*50
1*20
1*10
1*5
1*2
1*1

Julia

Using a linear optimizer for this is serious overkill, but why mot? <lang julia>using JuMP, GLPK

model = Model(GLPK.Optimizer) @variable(model, ones, Int) @variable(model, twos, Int) @variable(model, fives, Int) @variable(model, tens, Int) @variable(model, twenties, Int) @variable(model, fifties, Int) @variable(model, onehundreds, Int) @variable(model, twohundreds, Int) @constraint(model, ones >= 0) @constraint(model, twos >= 0) @constraint(model, fives >= 0) @constraint(model, tens >= 0) @constraint(model, twenties >= 0) @constraint(model, fifties >= 0) @constraint(model, onehundreds >= 0) @constraint(model, twohundreds >= 0) @constraint(model, 988 == 1ones +2twos + 5fives + 10tens + 20twenties + 50fifties + 100onehundreds + 200twohundreds)

@objective(model, Min, ones + twos + fives + tens + twenties + fifties + onehundreds + twohundreds)

optimize!(model) println("Optimized total coins: ", objective_value(model)) for val in [ones, twos, fives, tens, twenties, fifties, onehundreds, twohundreds]

   println("Value of ", string(val), " is ", value(val))

end

</lang>

Output:

Optimized total coins: 11.0
Value of ones is 1.0
Value of twos is 1.0
Value of fives is 1.0
Value of tens is 1.0
Value of twenties is 1.0
Value of fifties is 1.0
Value of onehundreds is 1.0
Value of twohundreds is 4.0

Ring

<lang ring> load "stdlib.ring"

see "working..." + nl see "Coins are:" + nl sum = 988

sumCoins = 0 coins = [1,2,5,10,20,50,100,200] coins = reverse(coins)

for n = 1 to len(coins)

   nr = floor(sum/coins[n])
   if nr > 0
      sumCoins= nr*coins[n]
      sum -= sumCoins    
      see "" + nr + "*" + coins[n] + nl
   ok

Output:

working...
Coins are:
4*200
1*100
1*50
1*20
1*10
1*5
1*2
1*1
done...