0
点赞
收藏
分享

微信扫一扫

221. 最大正方形——动态规划

class Solution {
public:
    int maximalSquare(vector<vector<char>>& matrix) {
        if(matrix.size() == 0)
            return 0;
        int maxSide = 0;
        int rows = matrix.size(), columns = matrix[0].size();
        vector<vector<int>> dp(rows, vector<int>(columns));
        for(int i = 0; i < rows; ++i){
            for(int j = 0; j < columns; ++j){
                if(matrix[i][j] == '1'){
                    if(i == 0 || j == 0)    //处理边缘情况
                        dp[i][j] = 1;
                    else
                        dp[i][j] = min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1])) + 1;  //取决于左上、上、左中最小的那个
                    maxSide = max(maxSide, dp[i][j]);   //更新正方形最大边长
                }
            }
        }
        return maxSide * maxSide;
    }
};

Accepted
77/77 cases passed (52 ms)
Your runtime beats 54.97 % of cpp submissions
Your memory usage beats 7.74 % of cpp submissions (17.8 MB)

举报

相关推荐

0 条评论