Find the least number of coins required that can make any change from 1 to 99 cents

Question

Recently I challenged my co-worker to write an algorithm to solve this problem:

Find the least number of coins required that can make any change from

Answer 1

After failing to find a good solution to this type of problem in PHP, I developed this function.

It takes any amount of money (up to $999.99) and returns an array of the minimum number of each bill / coin required to get to that value.

It first converts the value to an int in pennies (for some reason I would get errors at the very end when using standard float values).

The returned denominations are also in pennies (ie: 5000 = $50, 100 = $1, etc).

function makeChange($val)
{
    $amountOfMoney = intval($val*100);
    $cashInPennies = array(10000,5000,2000,1000,500,100,25,10,5,1);
    $outputArray = array();
    $currentSum = 0;
    $currentDenom = 0;

    while ($currentSum < $amountOfMoney) {
        if( ( $currentSum + $cashInPennies[$currentDenom] ) <= $amountOfMoney  ) {
            $currentSum = $currentSum + $cashInPennies[$currentDenom];
            $outputArray[$cashInPennies[$currentDenom]]++;
        } else {
            $currentDenom++;
        }
    }

    return $outputArray;

}

$change = 56.93;
$output = makeChange($change);

print_r($output);
echo "
Total number of bills & coins: ".array_sum($output);

=== OUTPUT ===

Array ( [5000] => 1 [500] => 1 [100] => 1 [25] => 3 [10] => 1 [5] => 1 [1] => 3 ) 
Total number of bills & coins: 11