【Luogu】P3313旅行（树链剖分）

　　题目链接

　　动态开点的树链剖分qwq。

　　跟小奇的花园一模一样，不做过多讲解。

　　

#include<cstdio>
#include<cstring>
#include<cctype>
#include<cstdlib>
#include<algorithm>
#define maxn 100010
#define mid ((l+r)>>1)
#define check(x) if(x==0)    x=++tot;
using namespace std;
inline long long read(){
    long long num=,f=;
    char ch=getchar();
    while(!isdigit(ch)){
        if(ch=='-')    f=-;
        ch=getchar();
    }
    while(isdigit(ch)){
        num=num*+ch-'';
        ch=getchar();
    }
    return num*f;
}

struct Edge{
    int next,to;
}edge[maxn*];
int head[maxn],num;
inline void add(int from,int to){
    edge[++num]=(Edge){head[from],to};
    head[from]=num;
}

int dfn[maxn];
int back[maxn],cnt;
int sum[maxn*],tot;
int mav[maxn*];
int root[maxn];
int ls[maxn*];
int rs[maxn*];
int top[maxn];
int size[maxn];
int son[maxn];
int deep[maxn];
int father[maxn];
int d[maxn];
int q[maxn];
int n,m;

void find(int x,int fa){
    size[x]=;deep[x]=deep[fa]+;
    for(int i=head[x];i;i=edge[i].next){
        int to=edge[i].to;
        if(to==fa)    continue;
        father[to]=x;
        find(to,x);
        size[x]+=size[to];
        if(son[x]==||size[son[x]]<size[to])    son[x]=to;
    }
}

void unionn(int x,int Top){
    dfn[x]=++cnt;    back[cnt]=x;
    top[x]=Top;
    if(son[x]==)    return;
    unionn(son[x],Top);
    for(int i=head[x];i;i=edge[i].next){
        int to=edge[i].to;
        if(to==father[x]||to==son[x])    continue;
        unionn(to,to);
    }
}

inline void pushup(int rt){
    sum[rt]=sum[ls[rt]]+sum[rs[rt]];
    mav[rt]=max(mav[ls[rt]],mav[rs[rt]]);
}

void update(int o,int num,int l,int r,int &rt){
    check(rt);
    if(l==r){
        sum[rt]=num;
        mav[rt]=num;
        return;
    }
    if(o<=mid)    update(o,num,l,mid,ls[rt]);
    else        update(o,num,mid+,r,rs[rt]);
    pushup(rt);
    return;
}

int quemax(int from,int to,int l,int r,int &rt){
    if(rt==)    return ;
    if(from<=l&&to>=r)    return mav[rt];
    int ans=;
    if(from<=mid)    ans=max(ans,quemax(from,to,l,mid,ls[rt]));
    if(to>mid)        ans=max(ans,quemax(from,to,mid+,r,rs[rt]));
    return ans;
}

int quesum(int from,int to,int l,int r,int &rt){
    if(rt==)    return ;
    if(from<=l&&to>=r)    return sum[rt];
    int ans=;
    if(from<=mid)    ans+=quesum(from,to,l,mid,ls[rt]);
    if(to>mid)        ans+=quesum(from,to,mid+,r,rs[rt]);
    return ans;
}

int askmax(int from,int to,int val){
    int ans=;
    while(top[from]!=top[to]){
        if(deep[top[from]]<deep[top[to]])    swap(from,to);
        ans=max(ans,quemax(dfn[top[from]],dfn[from],,n,root[val]));
        from=father[top[from]];
    }
    if(deep[from]>=deep[to])    swap(from,to);
    ans=max(ans,quemax(dfn[from],dfn[to],,n,root[val]));
    return ans;
}

int asksum(int from,int to,int val){
    int ans=;
    while(top[from]!=top[to]){
        if(deep[top[from]]<deep[top[to]])    swap(from,to);
        ans+=quesum(dfn[top[from]],dfn[from],,n,root[val]);
        from=father[top[from]];
    }
    if(deep[from]>=deep[to])    swap(from,to);
    ans+=quesum(dfn[from],dfn[to],,n,root[val]);
    return ans;
}

void chancol(int pos,int val){
    update(dfn[pos],,,n,root[q[pos]]);
    update(dfn[pos],d[pos],,n,root[val]);
    q[pos]=val;
}

void channum(int pos,int val){
    update(dfn[pos],val,,n,root[q[pos]]);
    d[pos]=val;
}

int main(){
    n=read(),m=read();
    for(int i=;i<=n;++i){
        d[i]=read();q[i]=read();
    }
    for(int i=;i<n;++i){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    find(,);
    unionn(,);
    for(int i=;i<=n;++i)    update(dfn[i],d[i],,n,root[q[i]]);
    for(int i=;i<=m;++i){
        char c[];
        scanf("%s",c);
        if(c[]=='C'){
            if(c[]=='C'){
                int x=read(),y=read();
                chancol(x,y);
            }
            else{
                int x=read(),y=read();
                channum(x,y);
            }
        }
        else if(c[]=='Q'){
            if(c[]=='S'){
                int x=read(),y=read();
                printf("%d\n",asksum(x,y,q[x]));
            }
            else{
                int x=read(),y=read();
                printf("%d\n",askmax(x,y,q[x]));
            }
        }
    }
    return ;
}

https://www.luogu.org/problemnew/show/P3313