【CCF】行车路线 改编Dijkstra

【AC】

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>

using namespace std;
typedef long long ll;
const int inf=0x3f3f3f3f;
const int maxn=5e2+2;
const int maxm=1e5+2;
int n,m;
struct edge{
    int t;
    int to;
    int nxt;
    ll w;
}e[2*maxm];
struct node{
    int id;
    ll d;
    ll fa;
    node(int _id,ll _d,ll _fa):id(_id),d(_d),fa(_fa){}
    bool operator < (const node& a) const{
        if(d!=a.d) return d>a.d;
        return fa>a.fa;
    }
};
int head[maxn];
int tot;
ll dis[maxn];
ll fa[maxn];
bool vis[maxn];
void init(){
    memset(head,-1,sizeof(head));
    tot=0;
}
void add(int t,int u,int v,ll w){
    e[tot].t=t;
    e[tot].to=v;
    e[tot].w=w;
    e[tot].nxt=head[u];
    head[u]=tot++;
}
ll dijkstra(int s){
    memset(dis,inf,sizeof(dis));
    memset(fa,inf,sizeof(fa));
    memset(vis,false,sizeof(vis));
    dis[s]=0,fa[s]=0;
    priority_queue<node> Q;
    Q.push(node(s,dis[s],fa[s]));
    while(!Q.empty()){
        node q=Q.top();
        Q.pop();
        int u=q.id;
        if(vis[u]) continue;
        vis[u]=true;
        for(int i=head[u];i!=-1;i=e[i].nxt){
            int t=e[i].t;
            int v=e[i].to;
            ll w=e[i].w;
            if(t==0){
                if(dis[u]+w<=dis[v]){
                    dis[v]=dis[u]+w;
                    fa[v]=0;
                    Q.push(node(v,dis[v],fa[v]));
                }
            }else{
                ll tmp=(fa[u]+w)*(fa[u]+w)+dis[u]-fa[u]*fa[u];
                if(tmp<dis[v]){
                    dis[v]=tmp;
                    fa[v]=fa[u]+w;
                    Q.push(node(v,dis[v],fa[v]));
                }else if(tmp==dis[v]){
                    if(fa[u]+w<fa[v]){
                        fa[v]=fa[u]+w;
                        Q.push(node(v,dis[v],fa[v]));
                    }
                }
            }
        }
    }
    return dis[n];
}
int main(){
    while(~scanf("%d%d",&n,&m)){
        init();
        int t,u,v;
        ll w;
        for(int i=1;i<=m;i++){
            scanf("%d%d%d%lld",&t,&u,&v,&w);
            add(t,u,v,w);
            add(t,v,u,w);
        }
        ll ans=dijkstra(1);
        printf("%lld\n",ans);
    }
    return 0;
}

原文地址：https://www.cnblogs.com/itcsl/p/9190610.html