déce. 19 最小生成树

https://www.luogu.com.cn/problem/P2330

题设就已经吧最小生成树的思想写出来了
其实就是个贪心

一遍过

#include<bits/stdc++.h>
using namespace std;
#define in Read()
typedef long long ll;

int in{
    int i=0,f=1; char ch=0;
    while((ch<'0'||ch>'9')&&ch!='-') ch=getchar();
    if(ch=='-') f=-1, ch=getchar();
    while('0'<=ch&&ch<='9') i=(i<<1)+(i<<3)+ch-48, ch=getchar();
    return i*f;
}

const int N=1e5+5;
struct edge{
    int u,v,c;
    edge(){};
    edge(int U,int V,int C){ u=U, v=V, c=C;}
}e[N];
int n,m,cnt,fa[N];

bool cmp(const edge &a, const edge &b){return a.c<b.c;}

int get(int x){return fa[x]==x?x:fa[x]=get(fa[x]);}

int main(){

    // freopen("1.in","r",stdin);

    n=in,m=in;
    for(int i=1;i<=m;++i){
        int u=in,v=in,c=in;
        e[++cnt]=edge(u,v,c);
    }

    cnt=0;
    sort(e+1,e+m+1,cmp);
    for(int i=1;i<=n;++i) fa[i]=i;

    for(int i=1;i<=m;++i){
        int u=get(e[i].u), v=get(e[i].v);
        if(u==v) continue;
        ++cnt;
        fa[u]=v;
        if(cnt==n-1){
            printf("%d %d\n",cnt,e[i].c);
            return 0;
        }
    }
    
}