uestc 482 Charitable Exchange 广搜+优先队列优化

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用优先队列对花费时间进行从大到小排序

#include<bits/stdc++.h>using namespace std;const int N=100000+1;typedef long long ll;struct edge{    ll u,v,w;}g[N];struct node{    ll m,t;    friend bool operator <(node n1,node n2)    {        return n2.t<n1.t;    }};int n;int cmp(edge a,edge b){    return a.v<b.v;}ll bfs(ll m){    int i,st=0;    priority_queue<node>pq;    node o,p;    p.m=1;    p.t=0;    pq.push(p);    while(!pq.empty())    {        p=pq.top();        pq.pop();        if(p.m>=m) return p.t;        for(i=st;i<n;i++)        {            if(g[i].v>p.m) break;            if(g[i].u<=p.m) continue;            o.m=g[i].u;            o.t=p.t+g[i].w;            pq.push(o);        }        st=i;    }    return -1;}int main(){    int _,i,cas=0;    ll m;    scanf("%d",&_);    while(_--)    {        scanf("%d%lld",&n,&m);        for(i=0;i<n;i++)            scanf("%lld%lld%lld",&g[i].u,&g[i].v,&g[i].w);        sort(g,g+n,cmp);        printf("Case #%d: %lld\n",++cas,bfs(m));    }    return 0;}

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