有亿点难

经过我0日的修炼，终于！————拉了托大的

#include <bits/stdc++.h>
using namespace std;
int n,m;
int sx,sy,fx,fy;
char a[45][45];
int vis[45][45];
bool ok=false;
int dx[] ={-1,1,0,0};
int dy[] = {0,0,-1,1};
void dfs(int x,int y){
    if(x == fx && y==fy){
        ok = true;
        return;
    }
    for (int i=0;i<4;i++){
        int nx = x+dx[i];
        int ny = y+dy[i];
        if(nx >= 1 && nx <= n && ny >= 1 && ny <= m&& a[nx][ny] == '.' && vis[nx][ny] == 0){
            vis[nx][ny] = 1;
            dfs(nx, ny);
            vis[nx][ny] = 0;
        }
    }
}
int main(){
	cin >>n>>m;
    cin >>sx>>sy>>fx>>fy;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin >>a[i][j];
        }
    }vis[sx][sy]=1;
    dfs(sx,sy);
    if(ok==true){
        cout<<"YES";
    }else{
        cout <<"NO";
    }
	return 0;
}