hdu 1072 广搜

 路径是可以重复走的，但是如果再一次走过时间重置点是没有意义的

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <queue>
using namespace std;


const int N = 100;
int mp[N][N];
struct Node {
    int x, y, step, time;
};
int m, n;
int dir[4][2] = {1,0, 0,1, -1,0, 0,-1};

int bfs(int x, int y) {
    queue<Node> que;
    Node start;
    start.x = x; start.y = y; start.step = 0; start.time = 6;
    que.push(start);
    while(!que.empty()) {
        Node cur = que.front();
        que.pop();
        if(cur.time == 0)
            continue;
        for(int i=0; i<4; i++) {
            int tx = cur.x+dir[i][0];
            int ty = cur.y+dir[i][1];
            Node nextstep;
            nextstep.x = tx; nextstep.y = ty;
            nextstep.step = cur.step+1; nextstep.time = cur.time-1;
            if(tx<0 || ty<0 || tx>=m || ty>=n) {
                continue;
            }
            if(mp[tx][ty] == 0) continue;
            if(mp[tx][ty] == 3) {
                if(nextstep.time>0)
                    return cur.step+1;
                else
                    continue;
            }
            if(mp[tx][ty] == 4) {
                if(nextstep.time>0){
                    nextstep.time = 6;
                    mp[tx][ty] = 0;         //只能走一次，走多了就没有意义了
                } else {
                    continue;
                }
            }
            que.push(nextstep);
        }
    }
    return -1;
}
int main()
{
    int t;
    cin>>t;
    while(t--) {
        cin>>m>>n;
        int x, y;
        for(int i=0; i<m; i++) {
            for(int j=0; j<n; j++) {
                cin>>mp[i][j];
                if(mp[i][j] == 2) {
                    x = i; y = j;
                }
            }
        }
        cout<<bfs(x, y)<<endl;
    }
    return 0;
}