leetcode-master/problems/0279.完全平方数.md

没有问你组合方式，而是问你最小个数

// 组合的逻辑

class Solution {
public:
    int numSquares(int n) {
        vector<int> sum;
        for (int i = 1; i * i <= n; i++) {
            sum.push_back(i * i);
        }
        vector<int> dp(n + 1, INT_MAX);
        dp[0] = 0;
        for (int i = 0; i < sum.size(); i++) {
            for (int j = 1; j <= n; j++) {
                if (j - sum[i] >= 0 && dp[j - sum[i]] != INT_MAX) {
                    dp[j] = min(dp[j - sum[i]] + 1, dp[j]);
                }
            }
        }
        return dp[n];
    }
};

// 排列的逻辑

class Solution {
public:
    int numSquares(int n) {
        vector<int> dp(n + 1, 0);
        for (int i = 0; i <= n; i++) {
            dp[i] = i; // 最多也就是i都是1组成的情况
            for (int j = 1; j * j <= i; j++) {
                dp[i] = min(dp[i - j * j] + 1, dp[i]);
            }
        }
        return dp[n];
    }
};