第一

#include <bits/stdc++.h>
using namespace std;
const int N = 2001;
int n,m,a[N][N],vis[N][N];
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
int flag=0;
void dfs (int x,int y)
{
	vis[x][y]=1;
	if(x==n and y==m)
	{
		flag=1;
		return;
			
	}	
	for(int i=0;i<4;++i)
	{
		int nx =dx[i]+x;
		int ny =dy[i]+y;
		if(nx>=1 and nx<=n and ny>=1 and ny<=m and vis[nx][ny]==0 and a[nx][ny]==0)
		{
			dfs(nx,ny);
		}
	}
}
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;++i)
		for(int j=1;j<=m;++j)
			cin>>a[i][j];
			
	dfs(1,1);
	if(flag==1)	cout<<"YES";
	else	cout<<"NO";
	
	return 0;

}