题解

#include<bits/stdc++.h>
using namespace std;
const  int N = 105;
int n,m;
bool mapp[N][N];
void input()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			char t;
			cin>>t; 
			if(t == '1')
			{
				mapp[i][j]=true;
			}
		}
	}
	return;
}
void DFS(int x,int y)
{
	if(x<=0 or y<=0 or x>n or y>m or mapp[x][y]==true)
	{
		return;
	}
	if(x==n and y==m)
	{
		cout<<"YES";
		exit(0);
	}
	mapp[x][y]=true;
	DFS(x+1,y);
	DFS(x-1,y);
	DFS(x,y+1);
	DFS(x,y-1); 
	
	return;
}
int main()
{
	input();
	DFS(1,1);
	cout<<"NO";
	return 0;
	
}