UVA-439， Knight Moves(深度优先搜索）

#include<iostream>
#include<queue>
#include<cstring>
#include<string>
#include<cstdio>
using namespace std;
struct Point
{
    int x_, y_;
    int route;
};
int dic[8][2] = {-1,2 ,1,2 ,2,1 ,2,-1 ,1,-2 ,-1,-2 ,-2,-1 ,-2,1};
int vis[10][10];        /*判断是否访问过*/
string fir, sec;
int ans;        /*记录最短路*/
int x1, y1, x2, y2;
void dfs()
{
    if(x1 == x2 && y1 == y2)
    {
        ans = 0;
        return ;
    }

    Point p;
    p.x_ = x1;
    p.y_ = y1;
    vis[x1][y1] = 1;
    p.route = 0;
    queue<Point> rr;
    rr.push(p);
    while(!rr.empty())
    {
//        if(x1 == x2 && y1 == y2)
//            break;
        Point q;
        for(int i = 0; i < 8; i++)
        {
            q.x_ = rr.front().x_ + dic[i][0];
            q.y_ = rr.front().y_ + dic[i][1];
            q.route = rr.front().route + 1;
            if(vis[q.x_][q.y_] == 1 || q.x_ < 0 || q.y_ < 0 || q.x_ > 7 || q.y_ > 7)
                continue;
            else
            {
                vis[q.x_][q.y_] = 1;
                rr.push(q);
                if(q.x_ == x2 && q.y_ == y2)
                {
                    ans = q.route;
                    break;                          /*找到了*/
                }
            }

        }

        if(q.x_ == x2 && q.y_ == y2)
            break;
        rr.pop();

    }
}
int main()
{
    while(cin >> fir >> sec)
    {
        memset(vis, 0, sizeof(vis));
        x1 = (int)fir[0] - 'a';
        y1 = (int)fir[1] - '0' - 1;
        x2 = (int)sec[0] - 'a';
        y2 = (int)sec[1] - '0' - 1;
        dfs();
        cout << "To get from " << fir << " to " << sec << " takes " << ans << " knight moves." << endl;

    }
}