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 <stdio.h>
#define max(p,q)((p)>(q)?(p):(q))
#define min(p,q)((p)<(q)?(p):(q))

int a[1500][1500];
int dp[1500][1500];
int main(){
	int h,w;
	scanf("%d%d",&h,&w);
	for(int i=0;i<h;i++)for(int j=0;j<w;j++)scanf("%d",&a[i+1][j+1]);
	int ans=0;
	for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)if(!a[i][j]){
		dp[i][j]=min(dp[i-1][j-1],min(dp[i-1][j],dp[i][j-1]))+1;
		ans=max(ans,dp[i][j]);
	}
	printf("%d\n",ans*ans);
}