Leetcode 279. Perfect Squares

class Solution {
public:
    int numSquares(int n) {
        vector<int> dp(n + 1, INT_MAX);
        dp[0] = 0;
        for(int i = 1; i <= n; i++ )
            for(int j = 1; j <= sqrt(i); j++)
                dp[i] = min(dp[i], dp[i - j * j] + 1);
        return dp[n];
    }
};