CodeForcesGym 100753E Change of Scenery

Change of Scenery

Time Limit: 10000ms

Memory Limit: 262144KB

This problem will be judged on CodeForcesGym. Original ID: 100753E
64-bit integer IO format: %I64d      Java class name: (Any)

 

解题：最短路

 #include <bits/stdc++.h>
 using namespace std;
 typedef pair<int,int> pii;
 const int maxn = ;
 struct arc{
     int to,cost,next;
     arc(int x = ,int y = ,int z = -){
         to = x;
         cost = y;
         next = z;
     }
 }e[];
 int head[maxn],cnt[maxn],d[maxn],tot,N,M,K;
 void add(int u,int v,int w){
     e[tot] = arc(v,w,head[u]);
     head[u] = tot++;
 }
 priority_queue<pii,vector<pii>,greater<pii>>q;
 bool done[maxn];
 void dijkstra(){
     while(!q.empty()) q.pop();
     memset(d,0x3f,sizeof d);
     memset(cnt,,sizeof cnt);
     q.push(pii(d[] = ,cnt[] = ));
     while(!q.empty()){
         int u = q.top().second;
         q.pop();
         if(done[u]) continue;
         done[u] = true;
         for(int i = head[u]; ~i; i = e[i].next){
             if(d[e[i].to] > d[u] + e[i].cost){
                 d[e[i].to] = d[u] + e[i].cost;
                 cnt[e[i].to] = cnt[u];
                 q.push(pii(d[e[i].to],e[i].to));
             }else if(d[e[i].to] == d[u] + e[i].cost)
                 cnt[e[i].to]++;
         }
     }
 }
 int main(){
     int x,u,v,w;
     while(~scanf("%d%d%d",&N,&M,&K)){
         memset(head,-,sizeof head);
         while(K--) scanf("%d",&x);
         for(int i = tot = ; i < M; ++i){
             scanf("%d%d%d",&u,&v,&w);
             add(u,v,w);
             add(v,u,w);
         }
         dijkstra();
         puts(cnt[N] > ?"yes":"no");
     }
     return ;
 }
 /*
 3 3 3
 1 2 3
 1 2 1
 2 3 2
 1 3 3
 4 5 2
 1 4
 1 2 2
 2 4 1
 1 3 1
 3 4 2
 1 4 2
 */