HDU 3001 Travelling

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 int tri[] = {0,1,3,9,27,81,243,729,2187,6561,19683,59049};
18 int e[12][12],dp[59049][12],s[59049][12] = {0};
19 int main() {
20     int n,m,x,y,z;
21     for(int i = 0; i < 59049; i++) {
22         int tmp = i;
23         for(int k = 1; k <= 10; k++) {
24             s[i][k] = tmp%3;
25             tmp /= 3;
26         }
27     }
28     while(~scanf("%d %d",&n,&m)) {
29         for(int i = 1; i <= n; i++)
30             for(int j = 1; j <= n; j++) e[i][j] = INF;
31         for(int i = 0; i < m; i++) {
32             scanf("%d %d %d",&x,&y,&z);
33             if(e[x][y] > z) e[x][y] = e[y][x] = z;
34         }
35         for(int i = 0; i < tri[n+1]; i++)
36             for(int j = 1; j <= 10; j++) dp[i][j] = INF;
37         for(int i = 0; i <= 10; i++) dp[tri[i]][i] = 0;
38         int ans = INF;
39         for(int i = 0; i < tri[n+1]; i++) {
40             bool flag = true;
41             for(int j = 1; j <= n; j++) {
42                 if(s[i][j] == 0) flag = false;
43                 for(int k = 1; k <= n; k++){
44                     if(j == k || e[j][k] == INF || s[i][k] == 2) continue;
45                     int ns = i + tri[k];
46                     dp[ns][k] = min(dp[ns][k],dp[i][j] + e[j][k]);
47                 }
48             }
49             for(int k = 1; flag && k <= n; k++)
50                 ans = min(ans,dp[i][k]);
51         }
52         ans == INF?puts("-1"):printf("%d\n",ans);
53     }
54     return 0;
55 }