bzoj 3282: Tree

http://www.lydsy.com/JudgeOnline/problem.php?id=3282

大概又是一道lct的裸题

#include<cstdio>
#include<algorithm>
const int maxn = 320007;
inline int read() {
    int x=0,f=1;char c=getchar();
    while(c<'0'||c>'9') {
        if(c=='-')f=-1;c=getchar();
    }
    while(c<='9'&&c>='0') {
        x=x*10+c-'0',c=getchar();
    }
    return x*f;
}
#define lc ch[x][0]
#define rc ch[x][1]
bool rev[maxn];
int stack[maxn],top;
int ans[maxn],v[maxn];
int fa[maxn],ch[maxn][2];
bool isroot(int x) {
    return ch[fa[x]][1]!=x&&ch[fa[x]][0]!=x;
}
void update(int x){
    ans[x]=ans[lc]^ans[rc]^v[x];
}
void pushdown(int x) {
     if(rev[x]) {
        rev[x]=0;rev[lc]^=1;rev[rc]^=1;
        std::swap(lc,rc);
     }
     return;
}
void rotate(int x) {
    int y=fa[x],z=fa[y],d=(ch[y][1]==x)^1;
    if(!isroot(y)) ch[z][ch[z][1]==y]=x;
    fa[x]=z;
    ch[y][d^1]=ch[x][d],fa[ch[x][d]]=y;
    ch[x][d]=y;fa[y]=x;
    return update(y),update(x);
}
void splay(int x) {
    stack[++top]=x;
    for(int i=x;!isroot(i);i=fa[i]) 
        stack[++top]=fa[i];
    while(top)pushdown(stack[top--]);
    while(!isroot(x)) {
        int y=fa[x],z=fa[y];
        if(!isroot(y)) {
            if(ch[y][1]==x^ch[z][1]==y)rotate(x);
            else rotate(y);
        }
        rotate(x);
    }
    return ;
}
void access(int x) {
    for(int i=0;x;i=x,x=fa[x]) {
        splay(x),ch[x][1]=i,update(x);
    }
    return ;
}
void makeroot(int x) {
    access(x);splay(x);rev[x]^=1;
    return;
}
void split(int x,int y) {
    makeroot(x),access(y);return splay(y);
}
void cut(int x,int y) {
    split(x,y);
    ch[y][0]=fa[ch[y][0]]=0;
    return;
}
void link(int x,int y) {
    makeroot(x),fa[x]=y;return splay(x);
}
int find(int x) {
    for(access(x),splay(x);ch[x][0];x=ch[x][0]);
    return x;
}
int query(int x,int y) {
    split(x,y);
    return ans[y];
}
void modify(int x,int w) {
    access(x),splay(x),v[x]=w;
    return update(x);
}
int main() {
    int n,m;
    n=read(),m=read();
    for(int i=1;i<=n;++i) {
        v[i]=read();ans[i]=v[i];
    }
    for(int op,x,y,i=1;i<=m;++i) {
        op=read(),x=read(),y=read();
        if(!op) 
            printf("%d\n",query(x,y));
        else if(op==1) {
            if(find(x)!=find(y)) link(x,y);
        }
        else if(op==2) {
            if(find(x)==find(y))cut(x,y);
        }
        else modify(x,y);
    }
    return 0;
}