POJ 1797 Heavy Transportation

 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 const int maxn = 1010;
18 struct arc{
19     int to,w,next;
20     arc(int x = 0,int y = 0,int z = -1){
21         to = x;
22         w = y;
23         next = z;
24     }
25 };
26 arc e[200000];
27 int d[maxn],head[maxn],tot,n,m;
28 bool done[maxn];
29 void add(int u,int v,int w){
30     e[tot] = arc(v,w,head[u]);
31     head[u] = tot++;
32     e[tot] = arc(u,w,head[v]);
33     head[v] = tot++;
34 }
35 void dijkstra(){
36     for(int i = 1; i <= n; ++i){
37         d[i] = 0;
38         done[i] = false;
39     }
40     d[1] = INF;
41     priority_queue< pii,vector< pii >,less< pii > >q;
42     q.push(make_pair(0,1));
43     while(!q.empty()){
44         int u = q.top().second;
45         q.pop();
46         if(done[u]) continue;
47         done[u] = true;
48         for(int i = head[u]; ~i; i = e[i].next){
49             if(d[e[i].to] < min(d[u],e[i].w)){
50                 d[e[i].to] = min(d[u],e[i].w);
51                 q.push(make_pair(d[e[i].to],e[i].to));
52             }
53         }
54         if(done[n]) break;
55     }
56 }
57 int main() {
58     int T,u,v,w,cs = 1;
59     scanf("%d",&T);
60     while(T--){
61         scanf("%d %d",&n,&m);
62         memset(head,-1,sizeof(head));
63         for(int i = tot = 0; i < m; ++i){
64             scanf("%d %d %d",&u,&v,&w);
65             add(u,v,w);
66         }
67         dijkstra();
68         printf("Scenario #%d:\n%d\n\n",cs++,d[n]);
69     }
70     return 0;
71 }