题解

#include<bits/stdc++.h>
using namespace std;
const int N=50;
int n,m;
int sx,sy;
int ex,ey;
char mp[N][N];
bool vis[N][N];
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
struct node{
	int x,y;
};
int main(){
	cin>>n>>m;
	cin>>sx>>sy;
	cin>>ex>>ey;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			cin>>mp[i][j];
		}
	}
	queue<node>q;
	q.push({sx,sy});
	vis[sx][sy]=1;
	while(q.size()>0){
		node s=q.front();
		q.pop();
		for(int i=0;i<4;i++){
			node a;
			a.x=s.x+dx[i];
			a.y=s.y+dy[i];
			if(a.x>=1&&a.y>=1&&a.x<=n&&a.y<=m&&mp[a.x][a.y]=='.'&&vis[a.x][a.y]==0){
				vis[a.x][a.y]=1;
				q.push(a);
				if(a.x==ex&&a.y==ey){
					cout<<"YES\n";
					return 0;
				}
			}
		}
	}
	cout<<"NO\n";
	return 0;
}