leetcode 322. Coin Change

最新推荐文章于 2022-02-13 23:11:44 发布

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本文探讨了硬币找零问题的动态规划解决方案，通过具体的代码实现展示了如何计算组成特定金额所需的最少硬币数量。

322. Coin Change

You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1.

Example 1:
coins = [1, 2, 5], amount = 11
return 3 (11 = 5 + 5 + 1)

Example 2:
coins = [2], amount = 3
return -1.

Note:
You may assume that you have an infinite number of each kind of coin.

1.一看是动态规划就知道是这种做法。

class Solution {
public:
    int coinChange(vector<int>& coins, int amount)
    {
        vector<int> ret(amount + 1, -1);
        ret[0] = 0;
        for (int i = 1; i <= amount; i++)
        {
            for (int j = 0; j < coins.size(); j++)
            {
                if (coins[j] > i) continue;
                else if (coins[j] == i)
                {
                    ret[i] = 1;
                    break;
                }
                else    //该硬币比当前值小
                {
                    if (ret[i - coins[j]] != -1)
                    {
                        if (ret[i] == -1)
                            ret[i] = ret[i - coins[j]] + 1;
                        else
                            ret[i] = min(ret[i], ret[i - coins[j]] + 1);
                    }
                }
            }
        }
        return ret[amount];
    }
};