树链剖分膜版

十分weak的树链剖分初步

给一棵树，实现两个功能：

①给两个节点u,v，给u,v路上的每条边权值加a

②给两个节点u,v，求u,v路上所有边的权值之和

ps:在线操作

#include<cstdio>
#include<cstring>
#include<iostream>
#include<vector>
using namespace std;

inline int read(){
    char ch;
    int re=0;
    bool flag=0;
    while((ch=getchar())!='-'&&(ch<'0'||ch>'9'));
    ch=='-'?flag=1:re=ch-'0';
    while((ch=getchar())>='0'&&ch<='9')  re=(re<<1)+(re<<3)+ch-'0';
    return flag?-re:re;
}

struct edge{
    int to,next;
    edge(int to=0,int next=0):
        to(to),next(next){}
};

const int maxn=100001;

vector<edge> edges;
vector<edge> tree;
int head[maxn],tmp_head[maxn];
int n,q,root,cnt;
int fat[maxn],dep[maxn],siz[maxn],son[maxn],top[maxn],id[maxn];
//B[i]表示区间1...i变化量 
int B[101];
//C[i]表示区间1...i变化量的总和，有c[i]=b[i]*i 
int C[101];

inline void add_edge(int from,int to){
    edges.push_back(edge(to,head[from]));
    head[from]=++cnt;
    edges.push_back(edge(from,head[to]));
    head[to]=++cnt;
}

inline void add_tree(int from,int to){
    tree.push_back(edge(to,tmp_head[from]));
    tmp_head[from]=++cnt;
}

void init(){
    n=read();  q=read();  root=read();
    edges.push_back(edge(0,0));
    cnt=0;
    for(int i=1;i<n;i++){
        int from=read(),to=read();
        add_edge(from,to);
    }
}

void dfs_1(int x,int fa){
    fat[x]=fa;
    dep[x]=dep[fa]+1;
    siz[x]=1;
    int maxx=0;
    for(int ee=head[x];ee;ee=edges[ee].next)
        if(edges[ee].to!=fa){
            add_tree(x,edges[ee].to);
            dfs_1(edges[ee].to,x);
            if(siz[edges[ee].to]>maxx){
                maxx=siz[edges[ee].to];
                son[x]=edges[ee].to;
            }
            siz[x]+=siz[edges[ee].to];
        }
}

void dfs_2(int x){
    if(son[x]){
        top[son[x]]=top[x];
        id[son[x]]=++cnt;
        dfs_2(son[x]);
    }
    for(int ee=head[x];ee;ee=tree[ee].next)
        if(tree[ee].to!=son[x]){
            top[tree[ee].to]=tree[ee].to;
            id[tree[ee].to]=++cnt;
            dfs_2(tree[ee].to);
        }
}

void make(){
    cnt=0;
    dep[0]=0;
    tree.push_back(edge(0,0));
    dfs_1(root,0);
    swap(head,tmp_head);
    top[root]=root;
    cnt=0;
    dfs_2(root);
}

void ADD_B(int x, int c)
{
     for (int i=x; i>0; i-=i&(-i)) B[i] += c;
}

void ADD_C(int x, int c)
{
     for (int i=x; i<=n; i+=i&(-i)) C[i] += x * c;
}

int add(int left,int right,int c){
    ADD_B(right,c);  ADD_C(right,c);
    if(left-1){
        ADD_B(left-1,-c);
        ADD_C(left-1,-c);
    }
}

int SUM_B(int x)
{
    int s = 0;
    for(int i=x;i<=n;i+=i&(-i)) s+=B[i];
    return s;
}

int SUM_C(int x)
{
    int s=0;
    for (int i=x;i;i-=i&(-i)) s+=C[i];
    return s;
}

int SUM(int x)
{
    if (x) return SUM_B(x)*x+SUM_C(x-1);
    else return 0;
}

int sum(int left,int right){
    return SUM(right)-SUM(left-1);
}

void cha(int u,int v,int a){
    int f1=top[u],f2=top[v];
    while(f1!=f2){
        if(dep[f1]<dep[f2]){
            swap(f1,f2);
            swap(u,v);
        }
        add(id[f1],id[u],a);
        u=fat[f1];  f1=top[u];
    }
    if(u==v)  return;
    if(dep[u]<dep[v])  swap(u,v);
    add(id[son[v]],id[u],a);
}

int calc(int u,int v){
    int f1=top[u],f2=top[v];
    int len=0;
    while(f1!=f2){
        if(dep[f1]<dep[f2]){
            swap(f1,f2);
            swap(u,v);
        }
        len+=sum(id[f1],id[u]);
        u=fat[f1];  f1=top[u];
    }
    if(u==v)  return len;
    if(dep[u]<dep[v])  swap(u,v);
    len+=sum(id[son[v]],id[u]);
    return len;
}

void solve(){
    for(int i=0;i<q;i++){
        int op=read(),ss=read(),tt=read();
        if(op){
            int a=read();
            cha(ss,tt,a);
        }
        else{
            printf("%d
",calc(ss,tt));
        }
    }
}

int main(){
    //freopen("temp.in","r",stdin);
    init();
    make();
    solve();
    return 0;
}

---

她会好吗 还是更烂

对我而言 是另一天