LCT模板
# include <stdio.h>
# include <stdlib.h>
# include <iostream>
# include <algorithm>
# include <string.h>
# define IL inline
# define RG register
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long ll;
const int MAXN(1e5 + 10);
namespace LCT{
int S[MAXN];
struct Tree{ int fa, ch[2], rev; } t[MAXN];
IL void Pushdown(RG int x){
if(!t[x].rev) return;
swap(t[x].ch[0], t[x].ch[1]);
t[x].rev = 0; t[t[x].ch[0]].rev ^= 1; t[t[x].ch[1]].rev ^= 1;
}
IL bool Son(RG int x){ return t[t[x].fa].ch[1] == x; }
IL bool Isroot(RG int x){ return t[t[x].fa].ch[0] != x && t[t[x].fa].ch[1] != x; }
IL void Rot(RG int x){
RG int y = t[x].fa, z = t[y].fa, c = Son(x);
if(!Isroot(y)) t[z].ch[Son(y)] = x; t[x].fa = z;
t[y].ch[c] = t[x].ch[!c]; t[t[y].ch[c]].fa = y;
t[x].ch[!c] = y; t[y].fa = x;
}
IL void Splay(RG int x){
RG int top = 0; S[++top] = x;
for(RG int y = x; !Isroot(y); y = t[y].fa) S[++top] = t[y].fa;
while(top) Pushdown(S[top--]);
for(RG int y = t[x].fa; !Isroot(x); Rot(x), y = t[x].fa)
if(!Isroot(y)) Son(x) ^ Son(y) ? Rot(x) : Rot(y);
}
IL void Access(RG int x){ for(RG int y = 0; x; y = x, x = t[x].fa) Splay(x), t[x].ch[1] = y; }
IL void Makeroot(RG int x){ Access(x); Splay(x); t[x].rev ^= 1; }
IL int Findroot(RG int x){ Access(x); Splay(x); while(t[x].ch[0]) x = t[x].ch[0]; return x; }
IL void Split(RG int x, RG int y){ Makeroot(x); Access(y); Splay(y); }
IL void Link(RG int x, RG int y){ Makeroot(x); t[x].fa = y; }
IL void Cut(RG int x, RG int y){ Split(x, y); t[x].fa = t[y].ch[0] = 0; }
};
using namespace LCT;
IL ll Read(){
RG char c = getchar(); RG ll x = 0, z = 1;
for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + c - '0';
return x * z;
}
int n, m;
int main(RG int argc, RG char* argv[]){
RG char opt[10]; n = Read(); m = Read();
while(m--){
RG int x, y; scanf(" %s", opt); x = Read(); y = Read();
if(opt[0] == 'C') Link(x, y);
else if(opt[0] == 'D') Cut(x, y);
else if(opt[0] == 'Q') puts(Findroot(x) == Findroot(y) ? "Yes" : "No");
}
return 0;
}