My solution:

#Define the coins with value
#(Remark: Ruby Hashs are ordered, so this can be used).
VALUES = {
  #'$' => 100,
  :H => 50,
  :Q => 25,
  :D => 10,
  :N =>  5,
  :P =>  1,
}
# In: Get money in cents
# Out: Change the minimum quantity of coins
def make_change2(amount, values = VALUES)
  change = {}  
  values.each{|coin, value|
    num, amount = amount.divmod(value)
    change[coin] = num if num > 0
  }
  change
end

Test:

[23,100,42,91].each{|i|
 puts "%-4i: %-10s" % [ i, make_change2(i)]
 }

result:

23  : {:D=>2, :P=>3}
100 : {:H=>2}   
42  : {:Q=>1, :D=>1, :N=>1, :P=>2}
91  : {:H=>1, :Q=>1, :D=>1, :N=>1, :P=>1}

One advantage of my solution: You can add new coins very easy. Just add '$' => 100, to support a one dollar coin. (The name of the coin must be uniq!).

Or just give your own coin definition as parameter.

My solution:

#Define the coins with value
#(Remark: Ruby Hashs are ordered, so this can be used).
VALUES = {
  #'$' => 100,
  :H => 50,
  :Q => 25,
  :D => 10,
  :N =>  5,
  :P =>  1,
}
# In: Get money in cents
# Out: Change the minimum quantity of coins
def make_change(amount, values = VALUES)
  change = {}  
  values.each{|coin, value|
    num, amount = amount.divmod(value)
    change[coin] = num if num > 0
  }
  change
end

Test:

[23,100,42,91].each{|i|
 puts "%-4i: %-10s" % [ i, make_change(i)]
 }

result:

23  : {:D=>2, :P=>3}
100 : {:H=>2}   
42  : {:Q=>1, :D=>1, :N=>1, :P=>2}
91  : {:H=>1, :Q=>1, :D=>1, :N=>1, :P=>1}

One advantage of my solution: You can add new coins very easy. Just add '$' => 100, to support a one dollar coin. (The name of the coin must be uniq!).

Or just give your own coin definition as parameter, e.g. for Euros:

EUR_VALUES = {
  :'2EUR' => 200,
  :EUR => 100,
  50 => 50,
  20 => 20,
  10 => 10,
    5 =>  5,
    2 =>  2,
    1 =>  1,
}
[23,42,91,100,101].each{|i|
 puts "%-4iEUR-Cents: %-10s" % [ i, make_change(i, EUR_VALUES)]
 }

Result:

23  EUR-Cents: {20=>1, 2=>1, 1=>1}
42  EUR-Cents: {20=>2, 2=>1}
91  EUR-Cents: {50=>1, 20=>2, 1=>1}
100 EUR-Cents: {:EUR=>1} 
101 EUR-Cents: {:EUR=>1, 1=>1}

My solution:

#Define the coins with value
#(Remark: Ruby Hashs are ordered, so this can be used).
VALUES = {
  :H => 50,
  :Q => 25,
  :D => 10,
  :N =>  5,
  :P =>  1,
}
# In: Get money in cents
# Out: Change the minimum quantity of coins
VALUES = {
  '$' => 100,
  :H => 50,
  :Q => 25,
  :D => 10,
  :N =>  5,
  :P =>  1,
}
# In: Get money in cents
# Out: Change the minimum quantity of coins
def make_change2(amount, values = VALUES)
  change = {}  
  values.each{|coin, value|
    num, amount = amount.divmod(value)
    change[coin] = num if num > 0
  }
  change
end

Test:

[23,100,42,91].each{|i|
 puts "%-4i: %-10s" % [ i, make_change2(i)]
 }

result:

23  : {:D=>2, :P=>3}
100 : {:H=>2}   
42  : {:Q=>1, :D=>1, :N=>1, :P=>2}
91  : {:H=>1, :Q=>1, :D=>1, :N=>1, :P=>1}

One advantage of my solution: You can add new coins very easy. Just add '$' => 100, to support a one dollar coin. (The name of the coin must be uniq!).

Or just give your own coin definition as parameter.

My solution:

#Define the coins with value
#(Remark: Ruby Hashs are ordered, so this can be used).
VALUES = {
  #'$' => 100,
  :H => 50,
  :Q => 25,
  :D => 10,
  :N =>  5,
  :P =>  1,
}
# In: Get money in cents
# Out: Change the minimum quantity of coins
def make_change2(amount, values = VALUES)
  change = {}  
  values.each{|coin, value|
    num, amount = amount.divmod(value)
    change[coin] = num if num > 0
  }
  change
end

Test:

[23,100,42,91].each{|i|
 puts "%-4i: %-10s" % [ i, make_change2(i)]
 }

result:

23  : {:D=>2, :P=>3}
100 : {:H=>2}   
42  : {:Q=>1, :D=>1, :N=>1, :P=>2}
91  : {:H=>1, :Q=>1, :D=>1, :N=>1, :P=>1}

One advantage of my solution: You can add new coins very easy. Just add '$' => 100, to support a one dollar coin. (The name of the coin must be uniq!).

Or just give your own coin definition as parameter.