畅通工程续

 1 #include<iostream>
 2 #include<queue>
 3 #include<cstdio>
 4 #include<cstring>
 5 using namespace std;
 6 #include<vector>
 7 const int maxn = 205;
 8 vector <pair<int, int> > E[maxn];
 9 int dis[maxn];
10 int n, m,s,t;
11 void init()
12 {
13     for (int i = 0; i < maxn; i++)
14         E[i].clear(), dis[i] = 1e9;
15 }
16 void dit()
17 {
18     dis[s] = 0;
19     priority_queue<pair<int, int> > q;
20     q.push(make_pair(-dis[s], s));
21     while (!q.empty())
22     {
23         int te = q.top().second;
24         q.pop();
25         for (int i = 0; i < E[te].size(); i++)
26         {
27             int d = E[te][i].first;
28             int k = E[te][i].second;
29             if (dis[d] > dis[te] + k)
30             {
31                 dis[d] = dis[te] + k;
32                 q.push(make_pair(-dis[d], d));
33             }
34         }
35     }
36     if (dis[t] == 1e9)
37         cout << "-1" << endl;
38     else cout << dis[t] << endl;
39 }
40 int main()
41 {
42     while (cin >> n >> m)
43     {
44         init();
45         for (int i = 0; i < m; i++)
46         {
47             int t1, t2, t3;
48             scanf("%d %d %d", &t1, &t2, &t3);
49             E[t1].push_back(make_pair(t2, t3));
50             E[t2].push_back(make_pair(t1, t3));
51         }
52         scanf("%d %d", &s, &t);
53         dit();
54     }
55     return 0;
56 }