hdu 1175 连连看 [DFS]

题目链接：hdu 1175 连连看  [DFS]

转弯次数不超过两次。和前段时间做的cf那题几乎一样，我又贴一遍。。。最近好懈怠，不想写题。

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<cmath>
#include<queue>
#include<limits.h>
#define CLR(a,b) memset((a),(b),sizeof((a)))
using namespace std;
typedef long long ll;
const int N = 1001;
int n, m;
int sx, sy, ex, ey;
int flag;
int s[N][N];
bool vis[N][N][3][3];
bool check(int x, int y) {
    if(s[x][y] == 0 || x == ex && y == ey)
        return true;
    return false;
}
void dfs(int x, int y, int d, int turn) {//上下：d = 1，左右：d = 2
    if(turn > 2 || vis[x][y][d][turn]) return;
    if(x == ex && y == ey) {
        flag = true;
        return;
    }
    vis[x][y][d][turn] = 1;
    if(x-1 >= 1 && !vis[x-1][y][1][turn+(d==2)]) {
        if(check(x-1,y))
            dfs(x-1, y, 1, turn + (d==2));
    }
    if(x+1 <= n && !vis[x+1][y][1][turn+(d==2)]) {
        if(check(x+1,y))
            dfs(x+1, y, 1, turn + (d==2));
    }
    if(y-1 >= 1 && !vis[x][y-1][2][turn+(d==1)]) {
        if(check(x,y-1))
            dfs(x, y-1, 2, turn + (d==1));
    }
    if(y+1 <= m && !vis[x][y+1][2][turn+(d==1)]) {
        if(check(x,y+1))
            dfs(x, y+1, 2, turn + (d==1));
    }
}
int main() {
    int i, j;
    while(~scanf("%d%d", &n, &m) , n && m) {
        for(i = 1; i <= n; ++i) {
            for(j = 1; j <= m; ++j) {
                scanf("%d", &s[i][j]);
            }
        }
        int t = 0;
        scanf("%d", &t);
        while(t--){
            flag = 0;
            CLR(vis, 0);

            scanf("%d%d%d%d", &sx, &sy, &ex, &ey);
            if(s[sx][sy] == s[ex][ey] && s[sx][sy] != 0)
                dfs(sx, sy, 0, 0);
            else {printf("NO\n");continue;}
           
            if(flag) puts("YES");
            else puts("NO");
        }
        
    }
    return 0;
}