public:

int maximalSquare(vector<vector<char>>& matrix) {

int ans = 0;

vector<vector<int>> dp(matrix.size()+1, vector<int>(matrix[0].size()+1,0));

for(int i=0; i<matrix.size(); i++){

for(int j=0; j<matrix[i].size();j++){

if(matrix[i][j] == '1'){

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

ans = max(ans, dp[i+1][j+1]);

}

else{

dp[i+1][j+1] = 0;

}

}

}

cout<<ans<<endl;

return ans;

}

Solution s;

vector<vector<char>> matrix = {{'1','0','1','0','0'},{'1','0','1','1','1'},{'1','1','1','1','1'},{'1','0','0','1','0'}};

cout<<s.maximalSquare(matrix)<<endl;

return 0;

}