[LeetCode 221] Maximal Square

Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 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

solution:

DP, f(x,y) represents length of the right-bottom node of square,

ifmatrix[i][j] == 1, f(x,y) = Math.min(f(x-1,y), f(x,y-1),f(x-1,y-1))+1;

public int maximalSquare(char[][] matrix) {
        int n = matrix.length;
        if(n<=0) return 0;
        int m = matrix[0].length;
        int max = 0;
        int[][] mat = new int[n][m];
        for(int i=0;i