一开始的思路是，先走驴子，之后走老虎，每次走的时候记录他们的达到该位置的步数，如果一样就可以相遇，特殊处理末尾。

但是没办法过，之后索性让他们一起走，一起修改移动的坐标，结果过了。。。

真心不知道错哪了。。

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<string>
#include<vector>
#include<stack>
#include<set>
#include<algorithm>
#include<map>
#include<sstream>
#include<cmath>
#include<queue>
#define INF (1 << 30)
#define eps (1e-10)
#define _PI acos(-1.0)
using namespace std;
/*=========================================
=========================================*/
#define MAXD 1000 + 10
int dir[4][2] = {{0,1},{1,0},{0,-1},{-1,0}}; //¶« ÄÏ Î÷ ±±
int n;
int dist1[MAXD][MAXD];
int dist2[MAXD][MAXD];
int ans_x,ans_y;
void dfs_d(int x,int y,int d,int dist){
    dist1[x][y] = dist;
    int _x = x;
    int _y = y;
    int _dist = dist;
    while(true){
        int t_x = _x;
        int t_y = _y;
        _x = _x + dir[d][0];
        _y = _y + dir[d][1];
        if(_x >= 0 && _x < n && _y >=0 && _y < n && dist1[_x][_y] == -1){
            _dist ++;
            dist1[_x][_y] = _dist;
        }
        else{
            _x = t_x;
            _y = t_y;
            d = (d + 1) % 4;
            _x = _x + dir[d][0];
            _y = _y + dir[d][1];
            if(_x >= 0 && _x < n && _y >= 0 && _y < n && dist1[_x][_y] == -1){
                dfs_d(_x,_y,d,_dist + 1);
                return ;
            }
            else{
                return ;
            }
        }
    }
}
void dfs_t(int x,int y,int d,int dist){
    dist2[x][y] = dist;
    int _x = x;
    int _y = y;
    int _dist = dist;
    while(true){
        int t_x = _x;
        int t_y = _y;
        _x = _x + dir[d][0];
        _y = _y + dir[d][1];
        if(_x >= 0 && _x < n && _y >=0 && _y < n && dist2[_x][_y] == -1){
            _dist ++;
            dist2[_x][_y] = _dist;
        }
        else{
            _x = t_x;
            _y = t_y;
            d = (d + 3) % 4;
            _x = _x + dir[d][0];
            _y = _y + dir[d][1];
            if(_x >= 0 && _x < n && _y >= 0 && _y < n && dist2[_x][_y] == -1){
                dfs_t(_x,_y,d,_dist + 1);
                return ;
            }
            else{
                return ;
            }
        }
    }
}
int main(){
    while(scanf("%d",&n) && n){
        int x , y, d;
        memset(dist1,-1,sizeof(dist1));
        memset(dist2,-1,sizeof(dist2));
        scanf("%d%d%d",&x,&y,&d);
        dfs_d(x,y,d,0);
        scanf("%d%d%d",&x,&y,&d);
        dfs_t(x,y,d,0);
        int ans_dist = INF;
        for(int i = 0 ; i < n ; i++){
            for(int j = 0 ; j < n ; j++)
                printf("%d ",dist1[i][j]);
            printf("\n");
        }
        for(int i = 0 ; i < n ; i++)
        for(int j = 0 ; j < n ; j++)if(dist1[i][j] != -1 && dist2[i][j] != -1){
                if(dist1[i][j] == dist2[i][j]){
                    if(ans_dist > dist1[i][j]){
                        ans_x = i;
                        ans_y = j;
                        ans_dist  = dist1[i][j];
                    }
                }
            }
        if(ans_dist < INF)
            printf("%d %d\n",ans_x,ans_y);
        else
            printf("-1\n");
    }
    return 0;
}

【hdu】The Donkey of Gui Zhou（搜索）