bzoj2049: [Sdoi2008]Cave 洞穴探测

bzoj2049: [Sdoi2008]Cave 洞穴探测

给ｎ个点，每次连接两个点或切断一条边，保证是树结构，多次询问两个点是否联通

Lct裸题

//Achen
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<vector>
#include<queue>
#include<ctime>
#include<cmath>
const int N=200000+7;
typedef long long LL;
using namespace std;
int n,m,ch[N][2],p[N],flip[N];
char op[20];

template<typename T> void read(T &x) {
    char ch=getchar(); x=0; T f=1;
    while(ch!='-'&&(ch<'0'||ch>'9')) ch=getchar();
    if(ch=='-') f=-1,ch=getchar();
    for(;ch>='0'&&ch<='9';ch=getchar()) x=x*10+ch-'0'; x*=f;
}

#define lc ch[x][0]
#define rc ch[x][1]
void down(int x) {
    if(!flip[x]) return;
    swap(lc,rc);
    flip[lc]^=1;
    flip[rc]^=1;
    flip[x]^=1;
} 

int isroot(int x) {return (ch[p[x]][0]!=x&&ch[p[x]][1]!=x);}

void rotate(int x) {
    int y=p[x],z=p[y],l=(x==ch[y][1]),r=l^1;
    if(!isroot(y)) ch[z][y==ch[z][1]]=x; p[x]=z;
    ch[y][l]=ch[x][r]; p[ch[x][r]]=y;
    ch[x][r]=y; p[y]=x;
}

void splay(int x) {
    static int g[N],top=0,tp;
    for(tp=x;!isroot(tp);tp=p[tp]) g[++top]=tp;
    g[++top]=tp;
    while(top) down(g[top--]);
    for(;!isroot(x);rotate(x)) {
        int y=p[x],z=p[y];
        if(!isroot(y))
            ((x==ch[y][1])^(y==ch[z][1]))?rotate(x):rotate(y); 
    }
}

void access(int x) {
    for(int t=0;x;x=p[t=x]) {
        splay(x);
        ch[x][1]=t;
    }
}

int findroot(int x) {
    access(x);
    splay(x);
    while(lc) x=lc;
    return x;
}

void newroot(int x) {
    access(x);
    splay(x);
    flip[x]^=1;
}

void lik(int x,int y) {
    newroot(x);
    splay(x);
    p[x]=y;
}

void del(int x,int y) {
    newroot(x);
    access(y);
    splay(y);
    if(ch[y][0]==x) ch[y][0]=p[x]=0; 
}

int main() {
#ifdef DEBUG
    freopen(".in","r",stdin);
    freopen(".out","w",stdout);
#endif
    read(n); read(m);
    while(m--) {
        scanf("%s",op);
        int x,y;
        read(x); read(y);
        if(op[0]=='Q') {
            if(findroot(x)==findroot(y)) printf("Yes\n");
            else printf("No\n");
        }
        if(op[0]=='C') lik(x,y);
        if(op[0]=='D') del(x,y);
    }
    return 0;
}
/*
200 5
Query 123 127
Connect 123    127
Query 123 127
Destroy    127    123
Query 123 127
*/