直接上程式碼吧：

class Solution(object):
    def coinChange(self, coins, amount):
        """
        :type coins: List[int]
        :type amount: int
        :rtype: int
        """
        if amount==0:
            return 0
        
        output = [0x7fffffff]*(amount+1)
        output[0] = 0
        for i in range(amount+1):
            for j in range(len(coins)):
                if i>=coins[j] and output[i-coins[j]]!=0x7fffffff:
                    output[i] = min(output[i],output[i-coins[j]]+1)
        
        if output[amount]==0x7fffffff:
            return -1
        else:
            return output[amount]