Leetcode--221-Maximal Square

Leetcode--221-Maximal Square 

221. Maximal Square

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• Total Accepted: 52663
• Total Submissions: 191381
• Difficulty: Medium
• Contributors: Admin

Given a 2D binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area.

For example, given the following matrix:

1 0 1 0 0
1 0 1 1 1
1 1 1 1 1
1 0 0 1 0

Return 4.

Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

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题解： dp最简单的形式

class Solution {
public:
    int maximalSquare(vector<vector<char>>& matrix) {
        if(matrix.size()==0 || matrix[0].size()==0){
            return 0; 
        }
        int row  = matrix.size(), column = matrix[0].size(); 
        vector<vector<int> > dp(row+1, vector<int>(column+1, 0)); 
        
        int ans = 0; 
        for(int i=0; i<row; ++i){
            for(int j=0; j<column; ++j){
                if( matrix[i][j] == '1' ){
                    dp[i+1][j+1] = min(dp[i][j], min(dp[i+1][j], dp[i][j+1])) + 1; 
                    if(ans < dp[i+1][j+1]){
                        ans = dp[i+1][j+1]; 
                    }
                }
            }
        }
        return (ans*ans); 
    }
};