bzoj2843: 极地旅行社

伪老年选手临时抱佛脚之LCT

正确率还挺高?只有两个小bug

然而不是说好caioj复习模板吗

啊？能升rank还能复习当然更好啦

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
using namespace std;

struct LCT
{
    int f,son[2];bool fz;
    int d,c;
    LCT(){f=0;son[0]=son[1]=0;fz=false;}
}tr[31000];

void update(int x)
{
    int lc=tr[x].son[0],rc=tr[x].son[1];
    tr[x].c=tr[lc].c+tr[rc].c+tr[x].d;
}
void reverse(int x)
{
    tr[x].fz=false;
    swap(tr[x].son[0],tr[x].son[1]);
    int lc=tr[x].son[0],rc=tr[x].son[1];
    if(lc!=0)tr[lc].fz=1-tr[lc].fz;
    if(rc!=0)tr[rc].fz=1-tr[rc].fz;
}
void rotate(int x,int w)
{
    int f=tr[x].f,ff=tr[f].f;
    int R,r;
    
    R=f;r=tr[x].son[w];
    tr[R].son[1-w]=r;
    if(r!=0)tr[r].f=R;
    
    R=ff;r=x;
         if(tr[R].son[0]==f)tr[R].son[0]=r;
    else if(tr[R].son[1]==f)tr[R].son[1]=r;
    tr[r].f=R;
    
    R=x;r=f;
    tr[R].son[w]=r;
    tr[r].f=R;
    
    update(f);
    update(x);
}
bool isroot(int x,int rt)
{
    int f=tr[x].f;
    if(f==rt||(tr[f].son[0]!=x&&tr[f].son[1]!=x))return true;
    else return false;
}
int ts,tmp[31000];
void splay(int x,int rt)
{
    ts=0;int i=x;
    while(isroot(i,rt)==false) 
    {
        tmp[++ts]=i;
        i=tr[i].f;
    }
    tmp[++ts]=i;
    while(ts>0) 
    {
        i=tmp[ts--];
        if(tr[i].fz==true)reverse(i);
    }
    //~~~~reverse
    
    while(isroot(x,rt)==false)
    {
        int f=tr[x].f,ff=tr[f].f;
        if(isroot(f,rt)==true)
        {
            if(tr[f].son[0]==x)rotate(x,1);
            else rotate(x,0);
        }
        else
        {
                 if(tr[ff].son[0]==f&&tr[f].son[0]==x){rotate(f,1);rotate(x,1);} 
            else if(tr[ff].son[1]==f&&tr[f].son[1]==x){rotate(f,0);rotate(x,0);}
            else if(tr[ff].son[0]==f&&tr[f].son[1]==x){rotate(x,0);rotate(x,1);} 
            else if(tr[ff].son[1]==f&&tr[f].son[0]==x){rotate(x,1);rotate(x,0);} 
        }
    }
}
//~~~splay

void access(int x)
{
    int y=0;
    while(x!=0)
    {
        splay(x,0);
        tr[x].son[1]=y;
        if(y!=0)tr[y].f=x;
        update(x);
        y=x;x=tr[x].f;
    }
}
int makeroot(int x)
{
    access(x);splay(x,0);
    tr[x].fz=1-tr[x].fz;
}

//-------------in---------------------

void Link(int x,int y)
{
    makeroot(x);tr[x].f=y;access(x);
}
int findroot(int x)
{
    access(x);splay(x,0);
    while(tr[x].son[0]!=0)x=tr[x].son[0];
    return x;
}
void change(int x,int d)
{
    makeroot(x);access(x);
    tr[x].d=d;tr[x].c=d;
}
int getsum(int x,int y)
{
    makeroot(x);
    access(y);splay(y,0);
    return tr[y].c;
}

//------------out---------------------

char ss[20];
int main()
{
    freopen("data.in","r",stdin);
    freopen("1.out","w",stdout);
    int n;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        scanf("%d",&tr[i].d), tr[i].c=tr[i].d;
    
    int Q,x,y,k;
    scanf("%d",&Q);
    while(Q--)
    {
        scanf("%s",ss+1);
        if(ss[1]=='b')
        {
            scanf("%d%d",&x,&y);
            if(findroot(x)==findroot(y))printf("no\n");
            else 
            {
                printf("yes\n");
                Link(x,y);
            }
        }
        else if(ss[1]=='p')
        {
            scanf("%d%d",&x,&k);
            change(x,k);
        }
        else
        {
            scanf("%d%d",&x,&y);
            if(findroot(x)!=findroot(y))printf("impossible\n");
            else printf("%d\n",getsum(x,y));
        }
    }
    return 0;
}