322.零钱兑换

class Solution(object):
    def coinChange(self, coins, amount):
        """
        :type coins: List[int]
        :type amount: int
        :rtype: int
        """
        n = len(coins) 
        dp = [float('inf')]*(amount + 1)  # 初始值为正无穷大
        dp[0] = 0 # 一定要初始化为0
        if amount == 0:
            return 0       
        for num in coins:
            for j in range(num,amount+1):
                if dp[j-num] !=float('inf'):
                    dp[j] = min(dp[j],dp[j-num]+1)
        if dp[amount] == float('inf'):
            return -1
        return dp[-1]

题目链接：322. 零钱兑换 - 力扣（LeetCode）