原题链接：Leetcode 1277. 统计全为 1 的正方形子矩阵

class Solution {
public:
    int countSquares(vector<vector<int>>& matrix) {
        int m = matrix.size();
        int n = matrix[0].size();
        vector<vector<int>> dp(m, vector<int>(n, 0));
        int res = 0;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                dp[i][j] = 0;
                if (matrix[i][j] == 1) {
                    if (i == 0 || j == 0) {
                        dp[i][j] = 1;
                    } else {
                        dp[i][j] = min(min(dp[i][j - 1], dp[i - 1][j]),
                                       dp[i - 1][j - 1]) +
                                   1;
                    }
                }
                res += dp[i][j];
            }
        }
        return res;
    }
};