【uoj207】 共价大爷游长沙

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
#define LL long long
#define inf (1ll<<30)
#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout)
using namespace std;

const int maxn=300010;
int S,n,m,id,tot,fa[maxn];

struct edge {int u,v,w;}e[maxn];
struct node {
	int son[2],val,sum,rev;
	int& operator [] (int x) {return son[x];}
}tr[maxn];

void reverse(int x) {
	swap(tr[x][0],tr[x][1]);tr[x].rev^=1;
}
void pushdown(int x) {
	if (tr[fa[x]][0]==x || tr[fa[x]][1]==x) pushdown(fa[x]);
	if (tr[x].rev) {
		if (tr[x][0]) reverse(tr[x][0]);
		if (tr[x][1]) reverse(tr[x][1]);
		tr[x].rev^=1;
	}
}
void pushup(int x) {
	tr[x].sum=tr[tr[x][0]].sum^tr[tr[x][1]].sum^tr[x].val;
}
void rotate(int x) {
	int y=fa[x],z=fa[y],l,r;
	l=tr[y][1]==x;r=l^1;
	if (tr[z][0]==y || tr[z][1]==y) tr[z][tr[z][1]==y]=x;
	fa[tr[x][r]]=y;fa[x]=z;fa[y]=x;
	tr[y][l]=tr[x][r];tr[x][r]=y;
	pushup(y);pushup(x);
}
void splay(int x) {
	pushdown(x);
	while (tr[fa[x]][0]==x || tr[fa[x]][1]==x) {
		int y=fa[x],z=fa[y];
		if (tr[z][0]==y || tr[z][1]==y) {
			if ((tr[z][0]==y) ^ (tr[y][0]==x)) rotate(x);
			else rotate(y);
		}
		rotate(x);
	}
}
void access(int x) {
	for (int y=0;x;y=x,x=fa[x]) {
		splay(x);tr[x].val^=tr[tr[x][1]].sum;
		tr[x].val^=tr[tr[x][1]=y].sum;
		pushup(x);
	}
}
void makeroot(int x) {
	access(x);splay(x);reverse(x);
}
void link(int x,int y) {
	makeroot(x);makeroot(y);  //一定要makeroot(y)，否则无法更新y所在的splay上祖先的信息
	fa[x]=y;tr[y].val^=tr[x].sum;
	pushup(y);
}
void cut(int x,int y) {
	makeroot(x);access(y);splay(y);
	fa[x]=tr[y][0]=0;pushup(y);
}
void modify(int x,int val) {
	access(x);splay(x);
	tr[x].val^=val;tr[x].sum^=val;
}
bool query(int x,int y) {
	makeroot(x);access(y);  //access以后，y在实树上的儿子全为它的虚儿子
	return tr[y].val==S ? 1 : 0;
}

int main() {
	scanf("%d%d%d",&id,&n,&m);
	for (int x,y,i=1;i<n;i++) {
		scanf("%d%d",&x,&y);
		link(x,y);
	}
	for (int op,x,y,z,i=1;i<=m;i++) {
		scanf("%d",&op);
		if (op==1) {
			scanf("%d%d",&x,&y);cut(x,y);
			scanf("%d%d",&x,&y);link(x,y);
		}
		if (op==2) {
			scanf("%d%d",&x,&y);
			e[++tot]=(edge){x,y,z=rand()};
			modify(x,z),modify(y,z);S^=z;
		}
		if (op==3) {
			scanf("%d",&x);S^=e[x].w;
			modify(e[x].u,e[x].w);modify(e[x].v,e[x].w);
		}
		if (op==4) {
			scanf("%d%d",&x,&y);
			puts(query(x,y) ? "YES" : "NO");
		}
	}
	return 0;
}