prim 堆优化+ kruskal 按秩优化

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#define pa pair<int,int>
using namespace std;
int n,num,dis[],ans,f[],head[];
struct node
{
    int u,v,pre,dis;
}e[*];
void Add(int from,int to,int dis)
{
    num++;
    e[num].dis=dis;
    e[num].u=from;
    e[num].v=to;
    e[num].pre=head[from];
    head[from]=num;
}
void Prim()
{
    priority_queue<pa,vector<pa>,greater<pa> >q;
    dis[]=;
    q.push(make_pair(,));
    while(!q.empty())
      {
          int k=q.top().second;
          q.pop();
          if(f[k])continue;
          f[k]=;
          ans+=dis[k];
          for(int i=head[k];i;i=e[i].pre)
            if(dis[e[i].v]>e[i].dis)
              {
                dis[e[i].v]=e[i].dis;
              q.push(make_pair(e[i].dis,e[i].v));
            }
      }
}
int main()
{
    scanf("%d",&n);
        num=;
        int x;
        memset(dis,/,sizeof(dis));
        memset(f,,sizeof(f));
        memset(head,,sizeof(head));
        for(int i=;i<=n;i++)
          for(int j=;j<=n;j++)
            {
              scanf("%d",&x);
              if(i!=j)Add(i,j,x);
            }
        ans=;
        Prim();
        printf("%d\n",ans);
    return ;
}

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define ll long long
#define maxn 100010
using namespace std;
int n,m,fa[maxn],deep[maxn];
ll ans;
struct node
{
    int u,v,dis;
}e[maxn];
int init()
{
    int x=;char s;bool f=;s=getchar();
    while(s<''||s>''){if(s=='-')f=;s=getchar();}
    while(s>=''&&s<=''){x=x*+s-'';s=getchar();}
    if(f)return -x;return x;
}
int cmp(const node &x,const node &y)
{
    return x.dis<y.dis;
}
int find(int x)
{
    if(x!=fa[x])fa[x]=find(fa[x]);
    return fa[x];
}
void unionn(int x,int y)
{
    if(deep[x]<=deep[y])
      {
        fa[x]=y;
         if(deep[x]==deep[y])
          deep[x]++;
      }
    else fa[y]=x;
}
int main()
{
    n=init();m=init();
    int x,y,z;
    for(int i=;i<=n;i++)fa[i]=i;
    for(int i=;i<=m;i++)
      {
          x=init();y=init();z=init();
          e[i].u=x;e[i].v=y;e[i].dis=z;
      }
    sort(e+,e++m,cmp);
    for(int i=;i<=m;i++)
      {
          int r1=find(e[i].u);
          int r2=find(e[i].v);
          if(r1==r2)continue;
          ans+=e[i].dis;
          unionn(r1,r2);
      }
    printf("%lld\n",ans);
    return ;
}