楼上广搜，那我发个深搜

#include<iostream>
using namespace std;
int n;
int sx,sy,ex,ey;
bool vis[1005][1005];
int flag;
int dx[4]={-2,-2,2,2};
int dy[4]={-2,2,-2,2};
bool check(int x,int y){
    return 1<=x&&x<=n&&1<=y&&y<=n;
}
void dfs(int x,int y){
    if(x==ex&&y==ey){
        flag=1;
        return ;
    }
    for(int i=0;i<4;i++){
        int nx=x+dx[i];
        int ny=y+dy[i];
        if(!vis[nx][ny]&&check(nx,ny)){
            vis[nx][ny]=1;
            dfs(nx,ny);
        }
    }
}
int main(){
    cin>>n;
    cin>>sx>>sy>>ex>>ey;
    dfs(sx,sy);
    if(flag==1) cout<<"YES";
    else cout<<"NO";
}