- #include <bits/stdc++.h>
- using namespace std;
- typedef long long ll;
- const ll inf = 1e18;
- const int M = 1e5+7;
- int n,m,cnt,head[M],flag[M];
- struct edge
- {
- int v,nex;ll w;
- }e[M*5];
- void init(){
- cnt=0;memset(head,-1,sizeof(head));memset(flag,0,sizeof(flag));
- }
- void add(int u,int v,ll w){
- e[++cnt].v=v;e[cnt].w=w;e[cnt].nex=head[u];
- head[u]=cnt;
- }
- struct node
- {
- int index,level;ll dis;
- }d[M][2];
- void dijkstra(int s,int t){
- for(int i=1;i<=n;i++)
- for(int j=0;j<=1;j++) d[i][j].dis=inf,d[i][j].index=i,d[i][j].level=j;
- priority_queue<node> q;d[s][0].dis=0;q.push(d[s][0]);
- while(!q.empty()){
- int u=q.top().index,lv=q.top().level;
- if(flag[u]) continue;
- flag[u]=1;
- for(int i=head[u];~i;i=e[i].nex){
- int v=e[i].v;ll w=e[i].w;
- if(d[v][lv].dis>d[u][lv].dis+w){
- d[v][lv].dis=d[u][lv].dis+w;
- q.push(d[v][lv]);
- }
- if(lv==0&&d[v][lv+1].dis>d[u][lv].dis+w/2){
- d[v][lv+1].dis=d[u][lv].dis+w/2;
- q.push(d[v][lv+1]);
- }
- }
- }
- ll ans=min(d[t][0].dis,d[t][1].dis);
- printf("%lld\n",ans);
- }
- int main(){
- return 0;
- }
- View Code
- hdu 3499
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