C++模板：Dijkstra+优先队列

2023-11-04 12:32:16

#include <cstdio>  
#include <cstring> 
#include <queue> 
#include <utility> 

using 
namespace std;  

const 
int N=20005;  

const 
int INF=9999999;  

typedef 
pair<int,int>seg;  
priority_queue<seg,vector,greater >q;     

int 
d[N],head[N],u[N],v[N],w[N],next[N],n,m,a,b,c; 

bool 
vis[N];  

void 
build(){  

    memset(head,-1,sizeof(head)); 

    for(int 
e=1;e<=m;e++){  

        scanf("%d%d%d",&u[e],&v[e],&w[e]);  

        u[e+m]=v[e]; v[e+m]=u[e]; w[e+m]=w[e];  

        next[e]=head[u[e]]; head[u[e]]=e;  

        next[e+m]=head[u[e+m]]; head[u[e+m]]=e+m;  

    }  
}     

void 
Dijkstra(int 
src){  

    memset(vis,0,sizeof(vis));  

    for(int 
i=0;i<=n;i++) d[i]=INF;  

    d[src]=0;  

    q.push(make_pair(d[src],src));  

    while(!q.empty()){  

        seg now=q.top(); q.pop();  

        int 
x=now.second;  

        if(vis[x]) continue; vis[x]=true;  

        for(int 
e=head[x];e!=-1;e=next[e]) 

        if(d[v[e]]>d[x]+w[e]){  

            d[v[e]]=d[x]+w[e];  

            q.push(make_pair(d[v[e]],v[e]));  

        }   

    }  
}      

int 
main(){  

    while(~scanf("%d%d",&n,&m)&&n+m){build();Dijkstra(1);printf("%d\n",d[n]);}  

    return 
0;  
}

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C++模板：Dijkstra+优先队列

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