322.零钱兑换.py

#
# @lc app=leetcode.cn id=322 lang=python
#
# [322] 零钱兑换
#
# https://leetcode-cn.com/problems/coin-change/description/
#
# algorithms
# Medium (35.28%)
# Likes:    247
# Dislikes: 0
# Total Accepted:    25.2K
# Total Submissions: 70.1K
# Testcase Example:  '[1,2,5]\n11'
#
# 给定不同面额的硬币 coins 和一个总金额
# amount。编写一个函数来计算可以凑成总金额所需的最少的硬币个数。如果没有任何一种硬币组合能组成总金额，返回 -1。
# 
# 示例 1:
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# 输入: coins = [1, 2, 5], amount = 11
# 输出: 3 
# 解释: 11 = 5 + 5 + 1
# 
# 示例 2:
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# 输入: coins = [2], amount = 3
# 输出: -1
# 
# 说明:
# 你可以认为每种硬币的数量是无限的。
# 
#

# @lc code=start
class Solution(object):
    def coinChange(self, coins, amount):
        """
        :type coins: List[int]
        :type amount: int
        :rtype: int
        """
        dp=[float('inf')]*(amount+1)
        dp[0]=0
        for i in range(1,amount+1):
            for coin in coins:
                if i>=coin:
                    dp[i]=min(dp[i],dp[i-coin]+1)
        return dp[-1] if dp[-1]!=float('inf') else -1



        # @lc code=end