hdu-2544-最短路(SPFA模板)

题目链接

题意很清晰，入门级题目，适合各种模板，可用dijkstra, floyd, Bellman-ford, spfa

Dijkstra链接

Floyd链接

Bellman-Ford链接

SPFA链接

 1 /*
 2     Name:HDU-2544-最短路
 3     Copyright:
 4     Author:
 5     Date: 2018/4/17 10:34:47
 6     Description:
 7     SPFA
 8 */
 9 #include <cstring>
10 #include <cstdio>
11 #include <iostream>
12 #include <vector>
13 #include <queue>
14 #include <utility>
15 using namespace std; 
16 const int MAXN = 1010;
17 int  n, m;
18 vector <pair<int, int>> g[MAXN];
19 int dist[MAXN];
20 bool inQue[MAXN];
21 queue<int> que;
22 void spfa() {
23     memset(inQue, 0, sizeof(inQue));
24     memset(dist, 0x3f, sizeof(dist));
25     dist[1] = 0;
26     while (!que.empty()) que.pop();
27     que.push(1);
28     inQue[1] = true;
29     while (!que.empty()) {
30         int u = que.front();
31         que.pop();
32         inQue[u] = false;
33         for (int i=0; i<g[u].size(); i++) {
34             if(dist[u]+g[u][i].second < dist[g[u][i].first]) {
35                 dist[g[u][i].first] = dist[u] + g[u][i].second;
36                 if (!inQue[g[u][i].first]) {
37                     inQue[g[u][i].first] = true;
38                     que.push(g[u][i].first);
39                 }
40             }
41         }
42     }
43 }
44 int main()
45 {
46 //    freopen("in.txt", "r", stdin);
47     while (~scanf("%d %d", &n, &m) && (n+m)) {
48         for (int i=0; i<=100; i++) {
49             while (!g[i].empty()) {//  while
50                 g[i].pop_back();
51             }
52         }
53         for (int i=1; i<=m; i++) {
54             int a, b, c;
55             scanf("%d %d %d", &a, &b, &c);
56             g[a].push_back(make_pair(b, c));
57             g[b].push_back(make_pair(a, c));
58         }
59         spfa();
60         printf("%d\n", dist[n]);
61     }
62     return 0;
63 }

 

posted @ 2018-04-17 16:41  朤尧  阅读(240)  评论(0)  编辑  收藏  举报