nyoj 21-三个水杯

 1 //105738 jiaolinfeng 三个水杯 Accepted  68  4212 C/C++ 12-15 08:56:02 
 2 #include<iostream>
 3 #include<cstdio>
 4 #include<queue>
 5 #include<string.h>
 6 using namespace std;
 7 typedef struct
 8 {
 9     int cur[3];
10     int v[3];
11     int step;
12 }State;
13 State begin, end;
14 queue<State> q;
15 int vis[1000010];
16 int final(State s1, State s2)
17 {
18     return (s1.cur[0] == s2.cur[0] && s1.cur[1] == s2.cur[1] && s1.cur[2] == s2.cur[2]);
19 }
20 int hash(State s)
21 {
22     return (s.cur[0] * 10000 + s.cur[1] * 100 + s.cur[2]);
23 }
24 int main()
25 {
26     int tcases, i, j, ok, min;
27     scanf("%d", &tcases);
28     while(tcases--)
29     {
30         scanf("%d%d%d", &begin.v[0], &begin.v[1], &begin.v[2]);
31         begin.cur[0] = begin.v[0];
32         begin.cur[1] = begin.cur[2] = 0;
33         begin.step = 0;
34         scanf("%d%d%d", &end.cur[0], &end.cur[1], &end.cur[2]);
35         ok = 0;
36         memset(vis, 0, sizeof(vis));
37         q.push(begin);
38         vis[myhash(begin)] = 1;
39         while(!q.empty())
40         {
41             State u = q.front();
42             q.pop();
43             if(final(u, end))
44             {
45                 printf("%d\n", u.step);
46                 ok = 1;
47                 break;
48             }
49             for(i = 0; i <= 2; i++)
50                 for(j = 0; j <= 2; j++)
51                     if(i != j)
52                     {
53                         min = u.v[j] - u.cur[j];
54                         if(u.cur[i] < min)
55                             min = u.cur[i];
56                         State v = u;
57                         v.cur[i] -= min;
58                         v.cur[j] += min;
59                         v.step = u.step +1;
60                         if(!vis[myhash(v)])
61                         {
62                             vis[myhash(v)] = 1;
63                             q.push(v);
64                         }
65                     }
66         }
67         if(!ok)
68         {
69             printf("-1\n");
70         }
71         while(!q.empty())
72         {
73             q.pop();
74         }
75     }
76     return 0;
77 }

bfs的经典题...有向图的遍历...一直没写出来因为我没想出来状态之间如何区别,看了前辈的代码才恍然大悟...第一次用STL队列...以
后要继续努力！