Maximal Square
Source
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
Return 4.
java
public class Solution {
public int maximalSquare(char[][] matrix) {
if (matrix == null || matrix.length == 0 || matrix[0].length == 0)
return 0;
int max = 0, n = matrix.length, m = matrix[0].length;
int[][] dp = new int[n + 1][m + 1];
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (matrix[i - 1][j - 1] == '1') {
dp[i][j] = Math.min(dp[i - 1][j - 1], Math.min(dp[i - 1][j], dp[i][j - 1])) + 1;
max = Math.max(max, dp[i][j]);
}
}
}
return max * max;
}
}
Reference
Maximal Square 最大正方形