221. Maximal Square(动态规划)

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

Example:

Input: 

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

Output: 4

dp[i][j] =  min(dp[i-1][j-1],min(dp[i-1][j],dp[i][j-1]))+1;

 class Solution {
 public:
     int maximalSquare(vector<vector<char>>& matrix) {
         int n = matrix.size();
         if(n==) return ;
         int m = matrix[].size();
         vector<vector<int> > dp(n+,vector<int>(m+,));
         int res =;
         for(int i = ;i <=n;i++)
             for(int j = ;j<=m;j++){

                 if(matrix[i-][j-]=='')
                     dp[i][j] =  min(dp[i-][j-],min(dp[i-][j],dp[i][j-]))+;
                     res  = max(res,dp[i][j]);
                 }

         return res*res;
     }

 };