一个LCT的模版题

写错了好多次..

代码:

#include<set>
#include<map>
#include<list>
#include<queue>
#include<stack>
#include<string>
#include<time.h>
#include<math.h>
#include<memory>
#include<vector>
#include<bitset>
#include<fstream>
#include<stdio.h>
#include<utility>
#include<sstream>
#include<string.h>
#include<iostream>
#include<stdlib.h>
#include<algorithm>
using namespace std;
const int maxn=300005;
const int inf=1999999999;
pair<int,int> p[300005];
struct node
{
    int val;
    int max_val;
    int tag;
    bool rev_tag;
    node * ch[2];
    node * father;
};
int top=0;
node * null;
node * a[maxn];
node * new_node(int x)
{
    static node a[300005];
    node * t=&a[top++];
    t->val=x;
    t->max_val=x;
    t->tag=0;
    t->rev_tag=0;
    t->ch[0]=null;
    t->ch[1]=null;
    t->father=null;
    return t;
}
void push_down(node * x)
{
    if (x->rev_tag)
    {
        swap(x->ch[0],x->ch[1]);
        x->ch[0]->rev_tag^=1;
        x->ch[1]->rev_tag^=1;
        x->rev_tag=false;
    }
    if (x->tag)
    {
        if (x->ch[0]!=null)
        {
            x->ch[0]->tag+=x->tag;
            x->ch[0]->max_val+=x->tag;
            x->ch[0]->val+=x->tag;
        }
        if (x->ch[1]!=null)
        {
            x->ch[1]->tag+=x->tag;
            x->ch[1]->max_val+=x->tag;
            x->ch[1]->val+=x->tag;
        }
        x->tag=0;
    }
}
int get_up(node * x)
{
    if (x->father->ch[0]==x) return 0;
    if (x->father->ch[1]==x) return 1;
    return -1;
}
void rotate(node * &x,int c)
{
    node * y=x->ch[c];
    x->ch[c]=y->ch[!c];
    y->ch[!c]->father=x;
    y->ch[!c]=x;
    y->father=x->father;
    x->father=y;
    y->max_val=x->max_val;
    x->max_val=max(x->val,max(x->ch[0]->max_val,x->ch[1]->max_val));
    x=y;
}
void splay(node * x)
{
    for (;;)
    {
        push_down(x->father->father);
        push_down(x->father);
        push_down(x);
        int t1=get_up(x);
        if (t1==-1) return;
        int t2=get_up(x->father);
        if (t2==-1)
        {
            x=x->father;
            rotate(x,t1);
            return;
        }
        int t3=get_up(x->father->father);
        if (t3==-1)
        {
            if (t1==t2)
            {
                x=x->father;
                x=x->father;
                rotate(x,t2);
                rotate(x,t1);
            }
            else
            {
                x=x->father;
                x=x->father;
                rotate(x->ch[t2],t1);
                rotate(x,t2);
            }
        }
        else
        {
            if (t1==t2)
            {
                x=x->father;
                x=x->father;
                x=x->father;
                rotate(x->ch[t3],t2);
                rotate(x->ch[t3],t1);
                x=x->ch[t3];
            }
            else
            {
                x=x->father;
                x=x->father;
                rotate(x->ch[t2],t1);
                x=x->father;
                rotate(x->ch[t3],t2);
                x=x->ch[t3];
            }
        }
    }
}
void access(node * &x)
{
    for (;;)
    {
        splay(x);
        if (x->father==null)
        {
            x->ch[1]=null;
            x->max_val=max(x->val,x->ch[0]->max_val);
            return;
        }
        splay(x->father);
        x->father->ch[1]=x;
        x->father->max_val=max(x->father->ch[0]->max_val,max(x->father->val,x->max_val));
    }
}
void evert(node * x)
{
    access(x);
    x->rev_tag=true;
}
void merges(node * x,node * y)
{
    evert(x);
    x->father=y;
}
int main()
{
    #ifdef absi2011
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
    int n;
    null=new_node(-inf);
    null->ch[0]=null;
    null->ch[1]=null;
    null->father=null;
    for (;scanf("%d",&n)!=-1;)
    {
        top=1;
        int i;
        for (i=1;i<n;i++)
        {
            int x,y;
            scanf("%d %d",&x,&y);
            x--;
            y--;
            p[i]=make_pair(x,y);
        }
        for (i=0;i<n;i++)
        {
            int x;
            scanf("%d",&x);
            a[i]=new_node(x);
        }
        for (i=1;i<n;i++)
        {
            merges(a[p[i].first],a[p[i].second]);
        }
        int m;
        scanf("%d",&m);
        for (i=0;i<m;i++)
        {
            int oper;
            scanf("%d",&oper);
            int x,y;
            if (oper==1)
            {
                scanf("%d%d",&x,&y);
                x--;
                y--;
                evert(a[x]);
                access(a[y]);
                if ((a[x]->father!=null)||(x==y))
                {
                    printf("-1\n");
                    continue;
                }
                merges(a[x],a[y]);
            }
            else if (oper==2)
            {
                scanf("%d%d",&x,&y);
                x--;
                y--;
                evert(a[x]);
                access(a[y]);
                if ((a[x]->father==null)||(x==y))
                {
                    printf("-1\n");
                    continue;
                }
                a[y]->ch[0]->father=null;
                a[y]->ch[0]=null;
                a[y]->max_val=a[y]->val;
            }
            else if (oper==3)
            {
                int z;
                scanf("%d",&z);
                scanf("%d%d",&x,&y);
                x--;
                y--;
                evert(a[x]);
                access(a[y]);
                if ((a[x]->father==null)&&(x!=y))
                {
                    printf("-1\n");
                    continue;
                }
                a[y]->tag+=z;
                a[y]->val+=z;
                a[y]->max_val+=z;
            }
            else
            {
                scanf("%d%d",&x,&y);
                x--;
                y--;
                evert(a[x]);
                access(a[y]);
                if ((a[x]->father==null)&&(x!=y))
                {
                    printf("-1\n");
                    continue;
                }
                printf("%d\n",a[y]->max_val);
            }
        }
        printf("\n");
    }
    return 0;
}