PLCT检查是什么洛谷P4234 最小差值生成树（lct动态维护最小生成树）

#include<map>
#include<set>
#include<queue>
#include<cmath>
#include<cstdio>
#include<string>
#include<vector>
#include<cstring>
#include<iostream>
#include<algorithm>
#define N 300010
#define M 350010
#define lson ch[x][0]
#define rson ch[x][1]
using namespace std;

int cnt[10010],max1,n,m,ans=0x3f3f3f3f;

struct node
{
    int from,to,w;
} e[N];

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

//lct begin

int tag[M],f[M],ch[M][2],sum[M];

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

int push_up(int x)

    if(e[sum[rson]].w>e[sum[x]].w)
    {
        sum[x]=sum[rson];
    }
}

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

int push_down(int x)

}

int rotate(int x)

    ch[x][!kd]=y;
    ch[y][kd]=xs;
    if(xs) f[xs]=y;
    f[y]=x;
    f[x]=z;
    push_up(y);
}

int push_all(int x)

    push_down(x);
}

int splay(int x)

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

int access(int x)
{
    for(int 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 print(int x)

//lct end

//dsu begin

int fa[M];

int init()
{
    for(int i=1; i<M; i++)
    {
        fa[i]=i;
    }
}

int find(int x)

int unity(int x,int y)

//dsu end

int main()
{
    init();
    scanf("%d%d",&n,&m);
    for(int i=1; i<=m; i++)
    {
        scanf("%d%d%d",&e[i].from,&e[i].to,&e[i].w);
    }
    sort(e+1,e+m+1,cmp);
    int tot=0;
    for(int i=m; i>=1; i--)

        else
        {
            split(e[i].from+m,e[i].to+m);
            int gg=sum[e[i].to+m];
            cut(e[gg].to+m,gg);
            cut(e[gg].from+m,gg);
            cnt[e[gg].w]--;
            cnt[e[i].w]++;
            while(!cnt[max1])
            {
                max1--;
            }
            if(tot==n-1) ans=min(ans,max1-e[i].w);
            link(e[i].to+m,i);
            link(e[i].from+m,i);
        }
    }
    printf("%d
",ans);
}