Elimination games

#include<bits/stdc++.h>

using namespace std;

const int N = 100;

int a[N][N];
int b[N][N];// Express （i,j） Can the grid of position be deleted , Can delete marked as 1, Cannot delete marked 0 

int main() {
    
	int n, m;
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++) {
    
		for (int j = 1; j <= m; j++) {
    
			scanf("%d", &a[i][j]);
			b[i][j] = 0;// initialization b 
		}
	}
	for(int i=1;i<=n;i++) {
    
		for(int j=1;j<=m;j++) {
    
			int u=i,d=i,l=j,r=j;
			int x=a[i][j];
			// from （i,j） Set out , Start in four directions up, down, left and right ,
			// When and a[i][j] Only when the values are the same can we move forward in the current direction ,
			// When the number of columns or rows is greater than or equal to 3 when , Mark  a[i][j] Can be eliminated  
			while(u>=1&&a[u][j]==x) u--;//
			while(d<=n&&a[d][j]==x) d++;
			while(r<=m&&a[i][r]==x) r++;
			while(l>=1&&a[i][l]==x) l--;
			if(d-u-1>=3||r-l-1>=3) 
			{
    
				b[i][j]=1;
			}
		}
	} 
	for(int i=1;i<=n;i++) {
    
		for(int j=1;j<=m;j++) {
    
			if(b[i][j]) printf("%d ",0);
			else printf("%d ",a[i][j]);
		}
		printf("\n");
	}
}