BZOJ 2049 LCT

    Orz 黄学长， 当然也要感谢自己（这次打的比较顺利，虽然题目操作很少，也比较简单），加油， 相信自己， 会更强大的， 但还是要虚心， 才会有更大的进步。 不过还是有点不懂，找个时间，问一下czl吧！

#include<cstdio>
#include<iostream>
#include<cstring>
#define rep(i,j,k) for(int i = j; i <= k; i++)
#define lc c[k][0]
#define rc c[k][1]
#define maxn 10233
using namespace std;

int n, m;
int read()
{
    int s = 0, t = 1; char c = getchar();
    while( !isdigit(c) ){
        if( c == '-' ) t = -1; c = getchar();
    }
    while( isdigit(c) ){
        s = s * 10 + c - '0'; c = getchar();
    }
    return s * t;
}

int c[maxn][2], pa[maxn];
bool rev[maxn];
int q[maxn];

inline bool root(int x)
{
    int k = pa[x];
    return lc != x && rc != x; 
}

void pushdown(int k)
{
    if( rev[k] ){
        rev[lc] ^= 1, rev[rc] ^= 1;
        swap(lc,rc);
        rev[k] ^= 1;
    }
} 

void rorate(int k)
{
    int fa = pa[k], gfa = pa[fa];
    int l = c[fa][1] == k, r = l ^ 1;
    if( !root(fa) ){
        c[gfa][c[gfa][1] == fa] = k;
    }    
    pa[k] = gfa, pa[c[k][r]] = fa, pa[fa] = k;
    c[fa][l] = c[k][r]; c[k][r] = fa; 
}

void splay(int k)
{
    int top = 0;
    q[++top] = k;
    for( int x = k; !root(x); x = pa[x] ){
        q[++top] = pa[x];
    }
    while( top ) pushdown(q[top--]);
    while( !root(k) ){
        int fa = pa[k], gfa = pa[fa];
        if( !root(fa) ){
            if( c[fa][0] == k ^ c[gfa][0] == fa ) rorate(k);
            else rorate(fa);
        }
        rorate(k);
    } 
}

void access(int x)
{
    for(int t = 0; x; t = x, x = pa[x]){
        splay(x), c[x][1] = t;
    }
}

void makeroot(int x)
{
    access(x), splay(x); rev[x] ^= 1;
}

void link(int x,int y)
{
    makeroot(x); pa[x] = y; splay(x);
}

void cut(int x,int y)
{
    makeroot(x); access(y), splay(y); c[y][0] = pa[x] = 0;
}

int find(int k)
{
    access(k); splay(k);
    while( lc ) k = lc;
    return k; 
}

bool solve(int x,int y)
{
    if( find(x) == find(y) ) return 1;
    else return 0;
}

int main()
{
    n = read(), m = read(); char c[10];
    rep(i,1,m){
        scanf("%s", c);
        int x = read(), y = read();
        if( c[0] == 'C' ){
            link(x,y);
        }
        if( c[0] == 'Q' ){
            if( solve(x,y) ) puts("Yes");
            else puts("No");
        }
        if( c[0] == 'D' ){
            cut(x,y);
        }
    }
    return 0;
}