CodeForcesGym 100753E Change of Scenery

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef pair<int,int> pii;
 4 const int maxn = 10010;
 5 struct arc{
 6     int to,cost,next;
 7     arc(int x = 0,int y = 0,int z = -1){
 8         to = x;
 9         cost = y;
10         next = z;
11     }
12 }e[2010000];
13 int head[maxn],cnt[maxn],d[maxn],tot,N,M,K;
14 void add(int u,int v,int w){
15     e[tot] = arc(v,w,head[u]);
16     head[u] = tot++;
17 }
18 priority_queue<pii,vector<pii>,greater<pii>>q;
19 bool done[maxn];
20 void dijkstra(){
21     while(!q.empty()) q.pop();
22     memset(d,0x3f,sizeof d);
23     memset(cnt,0,sizeof cnt);
24     q.push(pii(d[1] = 0,cnt[1] = 1));
25     while(!q.empty()){
26         int u = q.top().second;
27         q.pop();
28         if(done[u]) continue;
29         done[u] = true;
30         for(int i = head[u]; ~i; i = e[i].next){
31             if(d[e[i].to] > d[u] + e[i].cost){
32                 d[e[i].to] = d[u] + e[i].cost;
33                 cnt[e[i].to] = cnt[u];
34                 q.push(pii(d[e[i].to],e[i].to));
35             }else if(d[e[i].to] == d[u] + e[i].cost)
36                 cnt[e[i].to]++;
37         }
38     }
39 }
40 int main(){
41     int x,u,v,w;
42     while(~scanf("%d%d%d",&N,&M,&K)){
43         memset(head,-1,sizeof head);
44         while(K--) scanf("%d",&x);
45         for(int i = tot = 0; i < M; ++i){
46             scanf("%d%d%d",&u,&v,&w);
47             add(u,v,w);
48             add(v,u,w);
49         }
50         dijkstra();
51         puts(cnt[N] > 1?"yes":"no");
52     }
53     return 0;
54 }
55 /*
56 3 3 3
57 1 2 3
58 1 2 1
59 2 3 2
60 1 3 3
61 4 5 2
62 1 4
63 1 2 2
64 2 4 1
65 1 3 1
66 3 4 2
67 1 4 2
68 */