动态树模板题。。。涉及到的就是cut,link和findroot
#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 2000005
#define maxm 2000005
#define eps 1e-10
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
//#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head
struct node *null;
struct node
{
int rev;
node *ch[2], *fa;
inline bool d()
{
return fa->ch[1] == this;
}
inline bool isroot()
{
return fa == null || fa->ch[0] != this && fa->ch[1] != this;
}
inline void setc(node *p, int d)
{
ch[d] = p;
p->fa = this;
}
void rot()
{
node *f = fa, *ff = fa->fa;
int c = d(), cc = fa->d();
f->setc(ch[!c], c);
this->setc(f, !c);
if(ff->ch[cc] == f) ff->setc(this, cc);
else this->fa = ff;
}
void flip()
{
if(this == null) return;
swap(ch[0], ch[1]);
rev ^= 1;
}
void pushdown()
{
if(rev) {
ch[0]->flip();
ch[1]->flip();
rev = 0;
}
}
void go()
{
if(!isroot()) fa->go();
pushdown();
}
node* splay()
{
go();
while(!isroot()) {
if(!fa->isroot()) d() == fa->d() ? fa->rot() : rot();
rot();
}
return this;
}
node* access()
{
for(node *p = this, *q = null; p != null; q = p, p = p->fa) p->splay()->setc(q, 1);
return splay();
}
void makeroot()
{
access()->flip();
}
node* findroot()
{
node *p;
for(p = access(); p->ch[0] != null; p = p->ch[0]);
return p;
}
void link(node *p)
{
makeroot();
fa = p;
}
void cut(node *p)
{
p->makeroot();
this->access();
p->fa = ch[0] = null;
}
};
node *Node[maxn];
node pool[maxn];
node *tail;
char s[1005];
int n, m;
void init()
{
tail = pool;
null = tail++;
null->ch[0]= null->ch[1] = null->fa = null;
for(int i = 1; i <= n; i++) {
tail->ch[0] = tail->ch[1] = tail->fa = null;
tail->rev = 0;
Node[i] = tail++;
}
}
void work()
{
int a, b;
init();
while(m--) {
scanf("%s%d%d", s, &a, &b);
if(s[0] == 'C') Node[a]->link(Node[b]);
if(s[0] == 'D') Node[a]->cut(Node[b]);
if(s[0] == 'Q') {
if(Node[a]->findroot() == Node[b]->findroot()) printf("Yes\n");
else printf("No\n");
}
}
}
int main(void)
{
while(scanf("%d%d", &n, &m)!=EOF) work();
return 0;
}