Problem:
Largest Square

Given a matrix (H × W) which contains only 1 and 0, find the area of the largest square matrix which only contains 0s.

Input

H W
c1,1 c1,2 ... c1,W
c2,1 c2,2 ... c2,W
:
cH,1 cH,2 ... cH,W

In the first line, two integers H and W separated by a space character are given. In the following H lines, ci,j, elements of the H × W matrix, are given.

Output

Print the area (the number of 0s) of the largest square.

Constraints

1 ≤ H, W ≤ 1,400

Sample Input

4 5
0 0 1 0 0
1 0 0 0 0
0 0 0 1 0
0 0 0 1 0

Sample Output

4

Solution in C++ (judge verdict: Accepted)

#include <iostream>
#define HMAX 1400
#define WMAX 1400
using namespace std;
int main(){
	int H,W,ms = 0;
	int dp[HMAX+10][WMAX+10] = {};
	cin >> H >> W;
	for (int i = 1; i < H+1; ++i)
	{
		for (int j = 1; j < W+1; ++j)
		{
			cin >> dp[i][j];
			if(dp[i][j] == 0){
				dp[i][j] = 1;
			}else{
				dp[i][j] = 0;
			}
		}
	}
	for (int i = 1; i < H+1; ++i)
	{
		for (int j = 1; j < W+1; ++j)
		{
			if(dp[i][j] != 0){
				int m = min(dp[i-1][j-1],dp[i-1][j]);
				dp[i][j] += min(m,dp[i][j-1]);
				ms = max(ms,dp[i][j]);
			}
		}
	}
	cout << ms*ms << "\n";
	return 0;
}