[Swust OJ 409]--小鼠迷宫问题(BFS+记忆化搜索)

 1 #include <iostream>
 2 #include <queue>
 3 #include <cstring>
 4 #define maxn 101
 5 using namespace std;
 6 typedef long long LL;
 7 struct node{
 8     int sx, sy;
 9     node(int x, int y) :sx(x), sy(y){};
10     node(){};
11 };
12 int n, m, k, mpt[maxn][maxn], vis[maxn][maxn], dis[4][2] = { 1, 0, -1, 0, 0, -1, 0, 1 };
13 LL dp[maxn][maxn];
14 //dp[i][j]代表路径条数,mpt[i][j]最短路程的值
15 int BFS(int sx, int sy, int ex, int ey){
16     dp[sx][sy] = 1;//初始情况1条路径
17     vis[sx][sy] = 1;
18     node start(sx, sy);
19     queue<node>Q;
20     Q.push(start);
21     while (!Q.empty()){
22         node now = Q.front();
23         Q.pop();
24         if (now.sx == ex && now.sy == ey)//找到终点，返回最短路径
25             return mpt[now.sx][now.sy];
26         for (int i = 0; i < 4; i++){
27             int x = now.sx + dis[i][0];
28             int y = now.sy + dis[i][1];
29             if (x >= 1 && x <= n && y >= 1 && y <= m && mpt[x][y] != -1){
30                 if (!vis[x][y]){
31                     vis[x][y] = 1;
32                     mpt[x][y] = mpt[now.sx][now.sy] + 1;//最短路程加1
33                     dp[x][y] = dp[now.sx][now.sy];//直接赋值
34                     node next(x, y);
35                     Q.push(next);
36                 }
37                 else
38                     dp[x][y] += dp[now.sx][now.sy];
39             }
40         }
41     }
42     return -1;
43 }
44 int main(){
45     int x, y, sx, sy, ex, ey;
46     while (cin >> n >> m >> k){
47         memset(mpt, 0, sizeof(mpt));
48         memset(dp, 0, sizeof(dp));
49         memset(vis, 0, sizeof(vis));
50         for (int i = 0; i < k; i++){
51             cin >> x >> y;
52             mpt[x][y] = -1;//标记为障碍物
53         }
54         cin >> sx >> sy >> ex >> ey;
55         int ans = BFS(sx, sy, ex, ey);
56         if (ans == -1)
57             cout << "No Solution!" << endl;
58         else
59             cout << mpt[ex][ey] << endl << dp[ex][ey] << endl;
60     }
61     return 0;
62 }