Codeforces 165D Beard Graph 边权树剖+树状数组

#include "iostream"
#include "string.h"
#include "stack"
#include "queue"
#include "string"
#include "vector"
#include "set"
#include "map"
#include "algorithm"
#include "stdio.h"
#include "math.h"
#define ll long long
#define bug(x) cout<<x<<" "<<"UUUUU"<<endl;
#define mem(a,x) memset(a,x,sizeof(a))
#define mp(x,y) make_pair(x,y)
#define pb(x) push_back(x)
using namespace std;
const long long INF = 1e18+1LL;
const int inf = 1e9+1e8;
const int N=1e5+100;
const ll mod=1e9+7;

int to[N<<1],nex[N<<1],head[N],tot=2;
int siz[N],son[N],tip[N],top[N],dep[N],fa[N],cnt=0;
int n,m;
ll C[N];
map<int,int> M;
void add(int u, int v){
    to[tot]=v;
    nex[tot]=head[u];
    head[u]=tot++;
}
void dfs1(int u, int f){
    siz[u]=1;
    fa[u]=f;
    dep[u]=dep[f]+1;
    for(int i=head[u]; i!=-1; i=nex[i]){
        int v=to[i];
        if(v==f) continue;
        M[i>>1]=v;
        dfs1(v,u);
        siz[u]+=siz[v];
        if(siz[v]>siz[son[u]]) son[u]=v;
    }
}
void dfs2(int u, int tp){
    tip[u]=++cnt;
    top[u]=tp;
    if(son[u]) dfs2(son[u],tp);
    for(int i=head[u]; i!=-1; i=nex[i]){
        int v=to[i];
        if(v!=fa[u] && v!=son[u]) dfs2(v,v);
    }
}
int lowbit(int x){
    return (-x)&x;
}
void up(int x, ll c){
    while(x<=n){
        C[x]+=c;
        x+=lowbit(x);
    }
}
ll sum(int l, int r){
    ll ret=0;
    l--;
    while(l>0){
        ret-=C[l];
        l-=lowbit(l);
    }
    while(r>0){
        ret+=C[r];
        r-=lowbit(r);
    }
    return ret;
}
void get_sum(int u, int v){
    ll ans=0;
    while(top[u]!=top[v]){
        if(dep[top[u]] < dep[top[v]]) swap(u,v);
        ans+=sum(tip[top[u]], tip[u]);
        u=fa[top[u]];
    }
    if(dep[u] > dep[v]) swap(u,v); //u为LCA
    ans+=sum(tip[u],tip[v]);
    ans-=sum(tip[u],tip[u]);
    if(ans<0) cout<<"-1\n";
    else cout<<ans<<"\n";
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin>>n;
    mem(head,-1);
    int c,u,v;
    for(int i=1; i<n; ++i){
        cin>>u>>v;
        add(u,v);
        add(v,u);
    }
    dfs1(1,1);
    dfs2(1,1);
    for(int i=2; i<=n; ++i){
        up(i,1);
    }
    cin>>m;
    while(m--){
        cin>>c>>u;
        if(c==3){
            cin>>v;
            get_sum(u,v);
        }
        else if(c==2) up(tip[M[u]],-inf);
        else{
            //ll t=sum(1,tip[M[u]])-sum(1,tip[M[u]]-1);
            up(tip[M[u]],inf);
        }
    }
    return 0;
}