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[luogu4315]月下“毛景树”

luogu
联赛前复习一发树剖.不会告诉你WA了4发

#define ls x<<1,l,mid
#define rs x<<1|1,mid+1,r
#include<bits/stdc++.h>
using namespace std;
const int _=1e5+5;
int re(){
    int x=0,w=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
    return x*w;
}
int n,cnt,ans,ts;
int mx[_<<2],tag[_<<2],cov[_<<2];
int h[_],dfn[_],val[_],son[_],id[_],sz[_],fa[_],dep[_],t[_],f[_];
struct edge{int to,next,w,id;}e[_<<1];
void link(int u,int v,int w,int id){
    e[++cnt]=(edge){v,h[u],w,id};h[u]=cnt;
    e[++cnt]=(edge){u,h[v],w,id};h[v]=cnt;
}
void dfs(int u){
    sz[u]=1;
    for(int i=h[u];i;i=e[i].next){
        int v=e[i].to;
        if(v==fa[u])continue;
        fa[v]=u;dep[v]=dep[u]+1;f[e[i].id]=v;
        dfs(v);sz[u]+=sz[v];val[v]=e[i].w;
        if(sz[v]>sz[son[u]])son[u]=v;
    }
}
void dfs(int u,int tp){
    t[u]=tp;dfn[u]=++ts;id[ts]=u;
    if(son[u])dfs(son[u],tp);
    for(int i=h[u];i;i=e[i].next){
        int v=e[i].to;
        if(v^son[u]&&v^fa[u])dfs(v,v);
    }
}
void pu(int x){mx[x]=max(mx[x<<1],mx[x<<1|1]);}
void pt(int x,int v){mx[x]+=v;tag[x]+=v;}
void cv(int x,int v){mx[x]=v;cov[x]=v;tag[x]=0;}
void pd(int x){
    if(cov[x])cv(x<<1,cov[x]),cv(x<<1|1,cov[x]),cov[x]=0;
    if(tag[x])pt(x<<1,tag[x]),pt(x<<1|1,tag[x]),tag[x]=0;
}
void bu(int x,int l,int r){
    if(l==r){mx[x]=val[id[l]];return;}
    int mid=l+r>>1;bu(ls);bu(rs);pu(x);
}
void mem(int x,int l,int r,int ql,int qr,int v){
    if(ql<=l&&r<=qr){cv(x,v);return;}pd(x);
    int mid=l+r>>1;if(ql<=mid)mem(ls,ql,qr,v);
    if(qr>mid)mem(rs,ql,qr,v);pu(x);
}
void add(int x,int l,int r,int ql,int qr,int v){
    if(ql<=l&&r<=qr){pt(x,v);return;}pd(x);
    int mid=l+r>>1;if(ql<=mid)add(ls,ql,qr,v);
    if(qr>mid)add(rs,ql,qr,v);pu(x);
}
int qmax(int x,int l,int r,int ql,int qr){
    if(ql<=l&&r<=qr)return mx[x];pd(x);int mid=l+r>>1;
    int res=-1e9;if(ql<=mid)res=qmax(ls,ql,qr);
    if(qr>mid)res=max(res,qmax(rs,ql,qr));return res;
}
void solve(int u,int v,int w,int o){
    while(t[u]^t[v]){
        if(dep[t[u]]<dep[t[v]])swap(u,v);
        if(o==1)add(1,1,n,dfn[t[u]],dfn[u],w);
        if(!o)mem(1,1,n,dfn[t[u]],dfn[u],w);
        if(o==2)ans=max(ans,qmax(1,1,n,dfn[t[u]],dfn[u]));
        u=fa[t[u]];
    }
    if(u==v)return;
    if(dep[u]<dep[v])swap(u,v);
    if(o==1)add(1,1,n,dfn[v]+1,dfn[u],w);
    if(!o)mem(1,1,n,dfn[v]+1,dfn[u],w);
    if(o==2)ans=max(ans,qmax(1,1,n,dfn[v]+1,dfn[u]));
}
int main(){
    n=re();
    for(int i=1,u,v,w;i<n;i++){
        u=re(),v=re(),w=re();
        link(u,v,w,i);
    }
    dfs(1);dfs(1,1);bu(1,1,n);
    char op[8];int u,v;
    while(1){
        scanf("%s",op);
        if(op[1]=='t')break;
        u=re(),v=re();
        if(op[1]=='o')solve(u,v,re(),0);
        if(op[1]=='d')solve(u,v,re(),1);
        if(op[1]=='a'){ans=-1e9;solve(u,v,0,2);printf("%d\n",ans);}
        if(op[1]=='h')mem(1,1,n,dfn[f[u]],dfn[f[u]],v);
    }
    return 0;
}

[luogu4315]月下“毛景树”

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原文地址：https://www.cnblogs.com/sdzwyq/p/9927231.html