bzoj 2631: tree link-cut-tree

题目:

Description

一棵n个点的树，每个点的初始权值为1。对于这棵树有q个操作，每个操作为以下四种操作之一：

+ u v c：将u到v的路径上的点的权值都加上自然数c；

- u1 v1 u2 v2：将树中原有的边(u1,v1)删除，加入一条新边(u2,v2)，保证操作完之后仍然是一棵树；

* u v c：将u到v的路径上的点的权值都乘上自然数c；

/ u v：询问u到v的路径上的点的权值和，求出答案对于51061的余数。

Input

第一行两个整数n，q

接下来n-1行每行两个正整数u，v，描述这棵树

接下来q行，每行描述一个操作

Output

对于每个/对应的答案输出一行

题解

模板题

用了15mins打完,调了半小时

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long ll;
inline void read(ll &x){
    x=0;char ch;bool flag = false;
    while(ch=getchar(),ch<'!');if(ch == '-') ch=getchar(),flag = true;
    while(x=10*x+ch-'0',ch=getchar(),ch>'!');if(flag) x=-x;
}
const ll mod = 51061;
const ll maxn = 210010;
struct Node{
    Node *ch[2],*fa;
    ll mul,add,w,sum,tag;
    ll siz;
    void update();
    void pushdown();
    void set();
}*null;
Node mem[maxn],*it;
inline void init(){
    it = mem;null = it++;
    null->ch[0] = null->ch[1] = null->fa = null;
    null->mul = null->add = null->w = null->sum = 0;
    null->tag = null->siz = 0;
}
inline Node* newNode(ll w){
    Node *p = it++;p->ch[0] = p->ch[1] = p->fa = null;
    p->mul = 1;p->siz = 1;
    p->add = p->tag = 0;p->w = p->sum = w;return p;
}
inline void Node::update(){
    if(this == null) return;
    sum = (ch[0]->sum + ch[1]->sum + w) % mod;
    siz = (ch[0]->siz + ch[1]->siz + 1);
}
inline void Node::pushdown(){
    if(this == null) return;
    if(mul != 1){
        if(ch[0] != null){
            ch[0]->add = ch[0]->add*mul % mod;
            ch[0]->mul = ch[0]->mul*mul % mod;
            ch[0]->w = ch[0]->w*mul % mod;
            ch[0]->sum = ch[0]->sum*mul % mod;
        }
        if(ch[1] != null){
            ch[1]->add = ch[1]->add*mul % mod;
            ch[1]->mul = ch[1]->mul*mul % mod;
            ch[1]->w = ch[1]->w*mul % mod;
            ch[1]->sum = ch[1]->sum*mul % mod;
        }
        mul = 1;
    }
    if(add != 0){
        if(ch[0] != null){
            ch[0]->add = (ch[0]->add + add) % mod;
            ch[0]->sum = (ch[0]->sum + add*ch[0]->siz) % mod;
            ch[0]->w = (ch[0]->w + add) % mod;
        }
        if(ch[1] != null){
            ch[1]->add = (ch[1]->add + add) % mod;
            ch[1]->sum = (ch[1]->sum + add*ch[1]->siz) % mod;
            ch[1]->w = (ch[1]->w + add) % mod;
        }
        add = 0;
    }
    if(tag != 0){
        if(ch[0] != null) ch[0]->tag ^= 1;
        if(ch[1] != null) ch[1]->tag ^= 1;
        swap(ch[0],ch[1]);tag = 0;
    }
}
inline void rotate(Node *p,Node *x){
    ll k = p == x->ch[1];
    Node *y = p->ch[k^1],*z = x->fa;
    if(z->ch[0] == x) z->ch[0] = p;
    if(z->ch[1] == x) z->ch[1] = p;
    if(y != null) y->fa = x;
    p->fa = z;p->ch[k^1] = x;
    x->fa = p;x->ch[k] = y;
    x->update();p->update();
}
inline bool isroot(Node *p){
    return (p == null) || (p->fa->ch[0] != p && p->fa->ch[1] != p);
}
inline void Splay(Node *p){
    p->pushdown();
    while(!isroot(p)){
        Node *x = p->fa,*y = x->fa;
        y->pushdown();x->pushdown();p->pushdown();
        if(isroot(x)) rotate(p,x);
        else if((p == x->ch[0])^(x == y->ch[0])) rotate(p,x),rotate(p,y);
        else rotate(x,y),rotate(p,x);
    }p->update();
}
inline Node* Access(Node *x){
    for(Node *y = null;x != null;y = x,x = x->fa)
        Splay(x),x->ch[1] = y,x->update();
    return x;
}
inline void makeRoot(Node *x){
    Access(x);Splay(x);x->tag ^= 1;
}
inline void link(Node *x,Node *y){
    makeRoot(x);x->fa = y;
}
inline void cut(Node *x,Node *y){
    makeRoot(x);Access(y);Splay(y);
    y->ch[0] = y->ch[0]->fa = null;
    y->update();
}
inline void inc(Node *x,Node *y,ll w){
    makeRoot(x);Access(y);Splay(y);
    y->add += w;y->add %= mod;
    y->sum += w*y->siz;
    y->sum %= mod;
    y->w += w;y->w %= mod;
}
inline void mul(Node *x,Node *y,ll w){
    makeRoot(x);Access(y);Splay(y);
    y->add *= w;y->add %= mod;
    y->mul *= w;y->mul %= mod;
    y->sum *= w;y->sum %= mod;
    y->w *= w;y->w %= mod;
}
inline ll query(Node *x,Node *y){
    makeRoot(x);Access(y);Splay(y);
    return y->sum;
}
int main(){
    init();
    ll n,q;read(n);read(q);
    for(ll i=1;i<=n;++i) newNode(1);
    for(ll i=1,u,v;i<n;++i){
        read(u);read(v);
        link(mem+u,mem+v);
    }
    char ch;
    ll u,v,x;
    while(q--){
        while(ch = getchar(),ch<'!');
        if(ch == '+'){
            read(u);read(v);read(x);
            inc(mem+u,mem+v,x);
        }else if(ch == '-'){
            read(u);read(v);
            cut(mem+u,mem+v);
            read(u);read(v);
            link(mem+u,mem+v);
        }else if(ch == '*'){
            read(u);read(v);read(x);
            mul(mem+u,mem+v,x);
        }else if(ch == '/'){
            read(u);read(v);
            printf("%lld\n",query(mem+u,mem+v));
        }
    }
    getchar();getchar();
    return 0;
}