hdu-2544-最短路（Bellman-Ford算法模板）

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         man-ford 
 8 */
 9 #include <cstring>
10 #include <cstdio>
11 #include <iostream>
12 using namespace std; 
13 const int MAXN = 105;
14 const int INF = 0x3f3f3f3f;
15 int dis[MAXN], g[MAXN][MAXN], N, M;
16 bool v[MAXN];
17 void bellman_ford()
18 {
19     int i,j;
20     memset(dis, 0x3f, sizeof(dis));
21     dis[1]=0;
22     bool update=true;
23     while(update){
24         update=false;
25         for(i=1;i<=N;++i){
26             for(j=1;j<=N;++j){
27                 if(g[i][j]!=INF&&dis[j]>dis[i]+g[i][j]){
28                     dis[j]=dis[i]+g[i][j];
29                     update=true;
30                 }
31             }
32         }
33         if (!update) return;//优化 
34     }
35 }
36 int main()
37 {
38 //    freopen("in.txt", "r", stdin);
39     while (~scanf("%d %d", &N, &M) && (N+M)) {
40         memset(g, 0x3f, sizeof(g));
41         for (int i=0; i<M; i++) {
42             int a, b, c;
43             scanf("%d %d %d", &a, &b, &c);
44             if (g[a][b] > c) {
45                 g[a][b] = g[b][a] = c;
46             }
47         }
48         bellman_ford();
49         printf("%d\n", dis[N]);
50     }
51     return 0;
52 }

 

posted @ 2018-04-17 16:40  朤尧  阅读(394)  评论(0)  编辑  收藏  举报