https://leetcode.com/problems/maximal-square/

Solution.java

class Solution {
    public int maximalSquare(char[][] matrix) {
        if(matrix.length == 0) return 0;
        int[][] dp = new int[matrix.length][matrix[0].length];
        Integer max = 0;
        for(int i = 0;i<dp.length;i++) {
            //initialize
            if(matrix[i][0]=='1') {
                max = 1;
                dp[i][0] = 1;
            }
        }
        
        for(int j = 0;j<dp[0].length;j++) {
            if(matrix[0][j]=='1') {
                max = 1;
                dp[0][j]=1;   
            }
        }
            
        
        for(int i = 1;i<dp.length;i++) {
            for(int j = 1;j<dp[i].length;j++) {
                if(matrix[i][j]=='1'){
                    dp[i][j] = 1+Math.min(dp[i-1][j-1], Math.min(dp[i-1][j], dp[i][j-1]));
                    max = Math.max(max, dp[i][j]);
                }
            }
        }
        
        return max*max;
    }
    
}