堆优化dij求助
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堆优化dij求助
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Tobiichi_Origami楼主2022/7/28 14:25
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in int
typedef pair<int,int>pll;
struct edge{
    int next,to,w; 
}ed[2000010];
int he[2000010],tot;
bool vis[2000010];
int dis[2000010];
int n,m;
void insert(int u,int v,int w)
{
    tot++;
    ed[tot].to=v;
    ed[tot].w=w;
    ed[tot].next=he[u];
    he[u]=tot;  
} 
void dijkstra()
{
    priority_queue<pll,vector<pll>,greater<pll> >q;
    memset(dis,0x7f,sizeof(dis));
    memset(vis,1,sizeof(vis));
    dis[1]=0;
    q.push({0,1});
    while(q.size())
    {
        auto t=q.top();
        q.pop();
        int u=t.second,v=t.first;
        if(!vis[u]) continue;
        vis[u]=0;
        for(int i=he[u];i;i=ed[i].next)
        {
            int j=ed[i].to;
            if(dis[j]>v+ed[i].w)
            {
                dis[j]=v+ed[i].w;
                q.push({dis[j],j});
            }
        }
    }
}
signed main()
{
    cin>>n>>m;
    memset(he,-1,sizeof(he));
    for(int i=1;i<=m;i++)
    {
        int x,y,z;
        cin>>x>>y>>z;
        insert(x,y,z);
    }
    dijkstra();
    for(int i=1;i<=n;i++)
    {
        if(dis[i]==0x3f3f3f3f) cout<<-1<<" ";
        else cout<<dis[i]<<" ";
    }
    return 0;
}

就是卡了一个点过不去,请教一下各位dalao(我就是个小蒟蒻)

2022/7/28 14:25
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