UOJ #207. 共价大爷游长沙

题意：求S到T中某条边是否是必然经过。（动态树）

LCT，hash去打标记，是0就是合法的。

断边的时候，把要断的边标记打在新的路径上、

#include<bits/stdc++.h>
#define nrt(x) (ch[fa[x]][0]==x||ch[fa[x]][1]==x)
#define pii pair<int,int>
#define N 400007
using namespace std;
map<pii,int> mp;
inline void read(int &x){
    static char c;
    for (c=getchar();!isdigit(c);c=getchar());
    for (x=0;isdigit(c);c=getchar())x=x*10+c-48;
}
void write(int x){if (x<10) {putchar('0'+x); return;} write(x/10); putchar('0'+x%10);}
inline void writeln(int x){ if (x<0) putchar('-'),x*=-1; write(x); putchar('
'); }
inline void writel(int x){ if (x<0) putchar('-'),x*=-1; write(x); putchar(' '); }
inline int rod(){
    static int x=1887415157;
    return x^=x<<13,x^=x>>17,x^=x<<5;
}
int r[N],ch[N][2],lazy[N],key[N],fa[N];
void pushdown(int x) {
    if (nrt(x)) pushdown(fa[x]);
    if (r[x]) {
        swap(ch[x][1],ch[x][0]);
        if (ch[x][1]) r[ch[x][1]]^=1;
        if (ch[x][0]) r[ch[x][0]]^=1;
        r[x]=0;
    }
    if (lazy[x])  {
        key[x]^=lazy[x];
        if (ch[x][1]) lazy[ch[x][1]]^=lazy[x];
        if (ch[x][0]) lazy[ch[x][0]]^=lazy[x];
        lazy[x]=0;
    }
}
void pushup(int x){
    //
}
void rotate(int x){
    int y=fa[x],z=fa[y],l=ch[y][1]==x,r; r=l^1;
    if (nrt(y)) ch[z][ch[z][1]==y]=x;
    fa[x]=z; fa[y]=x; fa[ch[x][r]]=y;
    ch[y][l]=ch[x][r]; ch[x][r]=y; 
//    pushup(y); pushup(x);
}
void splay(int x){
    pushdown(x);
    while (nrt(x)){ 
        int y=fa[x],z=fa[y];
        if (nrt(y))
         if (ch[y][0]==x^ch[z][0]==y) rotate(x);
         else rotate(y);
        rotate(x);
    }
}
void access(int x){
    for (int y=0;x;x=fa[y=x]) {
        splay(x); ch[x][1]=y; //pushup(x)
    }
}
void beroot(int x){
    access(x); splay(x); r[x]^=1;
}
void split(int x,int y) {
    beroot(x); access(y); splay(y);
}
void link(int x,int y) {
    beroot(x); fa[x]=y;
}
int ppt;
int cut(int x,int y){
    beroot(x); access(y); splay(y);
    ppt=key[ch[y][0]]; ch[y][0]=0; fa[x]=0; return ppt;
}
int op,n,m,x,y,tot,a[N],b[N],k[N],ans,anw,Tot,gg,xx,yy,in;
signed main () {
    read(op);
    read(n); read(m);
    for (int i=1;i<n;i++)  {
      read(x),read(y), link(x,i+n),link(i+n,y); 
      if (x>y) swap(x,y); mp[pii(x,y)]=n+i;
      }
      Tot=2*n;
    while (m--) {
        read(op);
        if (op==1) {
            read(x); read(y); 
            if (x>y) swap(x,y);
            in=mp[pii(x,y)];
            cut(x,in); cut(y,in);
            gg=key[in];
            read(xx); read(yy); 
            if (xx>yy) swap(xx,yy); mp[pii(xx,yy)]=++Tot;
            link(xx,Tot); link(Tot,yy);
            split(x,y); lazy[y]^=gg;
        }
        if (op==2) {
            k[++tot]=rod();
            read(a[tot]); read(b[tot]); ans^=k[tot];
            split(a[tot],b[tot]); lazy[b[tot]]^=k[tot];
        }
        if (op==3) {
            read(x);
            ans^=k[x]; split(a[x],b[x]); lazy[b[x]]^=k[x];
        }
        if (op==4) {
            read(x); read(y);
            if (x>y) swap(x,y); in=mp[pii(x,y)];
            beroot(in);
            puts(key[in]==ans?"YES":"NO");
        }
    } return 0;
}