最短路 dijkstra+优先队列+临接表

Posted 2020-10-22 Schenker

http://acm.hdu.edu.cn/showproblem.php?pid=2544

 1 #include<iostream>
 2 #include<queue>
 3 #include<functional>
 4 #include<algorithm>
 5 #include<cstring>
 6 #include<vector>
 7 using namespace std;
 8 const int N = 1e3+5;
 9 const int INF = 1e7;
10 typedef pair<int, int> pll;
11 struct Node
12 {
13     int next;
14     int s;
15     Node(int nt, int d):next(nt), s(d){};
16 };
17 vector<Node> G[N];
18 int dis[N];
19 void dijkstra()
20 {
21     priority_queue<pll, vector<pll>, greater<pll> >q;
22     q.push(pll (0,1));// 距离 位置
23     while(!q.empty())
24     {
25         pll temp = q.top(); q.pop();
26         int x = temp.second, ss = temp.first;
27         if(dis[x]!= ss)
28            continue;
29         for(int i = 0; i < G[x].size(); i++)
30         {
31             int y = G[x][i].next, d = G[x][i].s;
32             if( dis[y] > dis[x] + d)
33             {
34                 dis[y]= dis[x]+d;
35                 q.push(pll (dis[y],y));
36             }
37         }
38     }
39 }
40 void init(int n)
41 {
42     for(int i = 1; i <= n; i++)
43         {
44             dis[i] = INF;
45             G[i].clear();
46         }
47 }
48 int main()
49 {
50     ios::sync_with_stdio(false);
51     cin.tie(0);
52     cout.tie(0);
53     int n, m;
54     while(cin >> n >> m, n+m)
55     {
56         init(n);
57         int x, y, d;
58         for(int i = 1; i <= m; i++)
59         {
60             cin >> x >> y >> d;
61             G[x].push_back(Node(y,d));
62             G[y].push_back(Node(x,d));
63         }
64         dis[1] = 0;
65         dijkstra();
66         cout << dis[n] << endl;
67     }
68     return 0;
69 }