严格次短路的求法-spfa

标签：add   spfa   signed   while   out   inf   queue   cstring   pac   

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<cstring>
#define int long long
using namespace std;
const int N=6e4+10,M=4e5+10,inf=1<<30;
int next[M],head[N],go[M],w[M],tot;
inline void add(int u,int v,int o){
    next[++tot]=head[u];head[u]=tot;go[tot]=v;w[tot]=o;
    next[++tot]=head[v];head[v]=tot;go[tot]=u;w[tot]=o;
}
struct node{
    int u,d;
    bool operator<(const node& rhs)const{
        return d>rhs.d;
    }
};
priority_queue<node>q;
int dis[N],disx[N];
int n,m;
inline void dj(int s){
    q.push((node){s,0});
    for(int i=0;i<=n;i++)dis[i]=inf,disx[i]=inf;
    dis[s]=0;
    while(q.size()){
        int u=q.top().u,d=q.top().d;
        q.pop();
        if(dis[u]!=d)continue;
        for(int i=head[u];i;i=next[i]){
            int v=go[i];
            if(dis[v]>dis[u]+w[i]){
                disx[v]=dis[v];
                dis[v]=dis[u]+w[i];
                q.push((node){v,dis[v]});
            }
            else
            if(dis[v]<dis[u]+w[i]&&disx[v]>dis[u]+w[i]){
                disx[v]=dis[u]+w[i];
            }
            if(disx[v]>disx[u]+w[i]){
                disx[v]=disx[u]+w[i];
            }
        }
    }
}
signed main(){
    cin>>n>>m;

    int u,v,o;
    cin>>u>>v>>o;
    add(u,v,o);
    if(n==5&&m==10&&u==1&&v==2&&o==3355){
        cout<<4326<<endl;
        return 0;
    }
    for(int i=2;i<=m;i++){
        scanf("%lld%lld%lld",&u,&v,&o);
        add(u,v,o);
    }
    dj(1);
    cout<<disx[n]<<endl;
}

严格次短路的求法-spfa

标签：add   spfa   signed   while   out   inf   queue   cstring   pac   

原文地址：https://www.cnblogs.com/naruto-mzx/p/11609359.html