HDU-6705 path （bfs）

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 
 4 const int maxn = 5e4+5;
 5 int n,m,k,t,q;
 6 typedef pair<int,int>p;
 7 typedef long long ll;
 8 vector<p>node[maxn];
 9 
10 ll ans[maxn];
11 int Q[maxn];
12 
13 struct Point
14 {
15     ll val;
16     int now,id;
17     Point(ll val,int now,int id):val(val),now(now),id(id){}
18     bool operator<(const Point &b)const{
19         return val > b.val;
20     }
21 };
22 
23 priority_queue<Point>que;
24 void bfs(int limit)
25 {
26     while(!que.empty())que.pop();
27    for(int i=1;i<=n;i++)sort(node[i].begin(),node[i].end());
28    for(int i=1;i<=n;i++)
29    {
30        if(!node[i].empty())que.push(Point(node[i][0].first,i,0));
31    }
32     int tot = 0;
33     while(!que.empty())
34     {
35         Point tmp = que.top();
36         que.pop();
37         ll cost = tmp.val;
38         int now = tmp.now;
39         int id = tmp.id;
40         if(++tot > limit)return;
41         ans[tot] = cost;
42         if(id < node[now].size() - 1)
43         {
44             que.push(Point(cost-node[now][id].first+node[now][id+1].first,now,id+1));
45         }
46         if(!node[node[now][id].second].empty())
47         {
48             que.push(Point(cost+node[node[now][id].second][0].first,node[now][id].second,0));
49         }
50     }
51 }
52 
53 int main()
54 {
55     scanf("%d",&t);
56     while(t--)
57     {
58         scanf("%d%d%d",&n,&m,&q);
59         int maxx = 0;
60         for(int i=1;i<=n;i++)node[i].clear();
61         for(int i=1;i<=m;i++)
62         {
63             int u,v,w;
64             scanf("%d%d%d",&u,&v,&w);
65             node[u].push_back(p(w,v));
66         }
67         for(int i=1;i<=q;i++)
68         {
69             scanf("%d",&Q[i]);
70             maxx = max(maxx,Q[i]);
71         }
72         bfs(maxx);
73         for(int i=1;i<=q;i++)
74         {
75             printf("%lld\n",ans[Q[i]]);
76         }
77     }
78 }