P3690 【模板】Link Cut Tree （动态树）

#include<cstdio>
void swap(int &a,int &b){a^=b^=a^=b;}
#define N 300005
int n,m,s[N],v[N],ch[2][N],fa[N],rev[N];
#define lc ch[0][x]
#define rc ch[1][x]
bool nrt(int x){return ch[0][fa[x]]==x||ch[1][fa[x]]==x;}
void up(int x){s[x]=s[lc]^v[x]^s[rc];}
void Rev(int x){swap(lc,rc);rev[x]^=1;}
void down(int x){if(rev[x])Rev(lc),Rev(rc),rev[x]=0;}
void fadown(int x){if(nrt(x))fadown(fa[x]); down(x);}
void turn(int x){
    int y=fa[x],z=fa[y],l=(ch[1][y]==x),r=l^1;
    if(nrt(y)) ch[ch[1][z]==y][z]=x;
    fa[ch[r][x]]=y; fa[x]=z; fa[y]=x;
    ch[l][y]=ch[r][x]; ch[r][x]=y;
    up(y); up(x);
}
void splay(int x){
    fadown(x);
    for(;nrt(x);turn(x)){
        int y=fa[x],z=fa[y];
        if(nrt(y)) turn((ch[1][y]==x)^(ch[1][z]==y)?x:y);
    }
}
void access(int x){for(int y=0;x;y=x,x=fa[x])splay(x),rc=y,up(x);}
void makert(int x){access(x);splay(x);Rev(x);}
int find(int x){
    access(x);splay(x);down(x);
    while(lc) x=lc,down(x);
    splay(x); return x;
}
void link(int x,int y){makert(x); if(find(y)!=x)fa[x]=y,up(y);}
void cut(int x,int y){
    makert(x);
    if(find(y)==x&&fa[y]==x&&!ch[0][y]) rc=fa[y]=0,up(x);
}
void split(int x,int y){makert(x);access(y);splay(y);}
int main(){
    scanf("%d%d",&n,&m); int q1,q2,q3;
    for(int i=1;i<=n;++i) scanf("%d",&v[i]);
    while(m--){
        scanf("%d%d%d",&q1,&q2,&q3);
        if(q1==0) split(q2,q3),printf("%d\n",s[q3]);
        else if(q1==1) link(q2,q3);
        else if(q1==2) cut(q2,q3);
        else splay(q2),v[q2]=q3;
    }return 0;
}