PLCT检查是什么洛谷P2387 [NOI2014]魔法森林（lct维护最小生成树）

#include<map>
#include<set>
#include<queue>
#include<cmath>
#include<cstdio>
#include<string>
#include<vector>
#include<cstring>
#include<iostream>
#include<algorithm>
#define lson ch[x][0]
#define rson ch[x][1]
using namespace std;

int n,m,f[200020],ch[200020][2],tag[200020],w[200020],sum[200020];
struct node
{
    int from,to,a,b;
} e[200020];

int cmp(node a,node b)
{
    return a.a<b.a;
}

int not_root(int now)
{
    int x=f[now];
    return lson==now||rson==now;
}

int push_up(int x)

    if(e[sum[x]].b<e[sum[rson]].b)
    {
        sum[x]=sum[rson];
    }
}

int rev(int x)
{
    swap(lson,rson);
    tag[x]^=1;
}

int push_down(int x)

}

int rotate(int x)

int push_all(int x)

    push_down(x);
}

int splay(int x)

        rotate(x);
    }
    push_up(x);
}

int access(int x)
{
    int y;
    for(y=0; x; y=x,x=f[x])
    {
        splay(x);
        rson=y;
        push_up(x);
    }
}

int make_root(int x)
{
    access(x);
    splay(x);
    rev(x);
}

int split(int x,int y)
{
    make_root(x);
    access(y);
    splay(y);
}

int find_root(int x)
{
    access(x);
    splay(x);
    while(lson)
    {
        push_down(x);
        x=lson;
    }
    return x;
}

int link(int x,int y)

int cut(int x,int y)

int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1; i<=m; i++)
    {
        scanf("%d%d%d%d",&e[i].from,&e[i].to,&e[i].a,&e[i].b);
    }
    sort(e+1,e+m+1,cmp);
    int ans=0x3f3f3f3f;
    for(int i=1; i<=m; i++)

        }
        else
        {
            link(e[i].from+m,i);
            link(e[i].to+m,i);
        }
        make_root(1+m);
        if(find_root(n+m)==1+m) ans=min(ans,e[i].a+e[sum[n+m]].b);
    }
    if(ans<0x3f3f3f3f) printf("%d
",ans);
    else puts("-1");
}