[SDOI2014]旅行

P3313 [SDOI2014]旅行

思路

有点恶心咯
每个信仰开一颗线段树记录
修改或者查询的时候去那一颗信仰线段树中查询就好
必须动态开点线段树
没有区间修改还算好写

错误

查询跳链写错了

#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
const int N=1e5+7;
int read() {
    int x=0,f=1;char s=getchar();
    for(;s>'9'||s<'0';s=getchar()) if(s=='-') f=-1;
    for(;s>='0'&&s<='9';s=getchar()) x=x*10+s-'0';
    return x*f;
}
vector<int> G[N];
int n,m,pj[N],xy[N];
int top[N],f[N],siz[N],idx[N],cnt,son[N],dep[N];
void dfs1(int u,int fa) {
    f[u]=fa;
    siz[u]=1;
    dep[u]=dep[fa]+1;
    for(vector<int>::iterator it=G[u].begin();it!=G[u].end();++it) {
        if(*it==fa) continue;
        dfs1(*it,u);
        siz[u]+=siz[*it];
        if(siz[son[u]] < siz[*it]) son[u]=*it;
    }
}
void dfs2(int u,int topf) {
    idx[u]=++cnt;
    top[u]=topf;
    if(!son[u]) return;
    dfs2(son[u],topf);
    for(std::vector<int>::iterator it=G[u].begin();it!=G[u].end();++it)
        if(!idx[*it]) dfs2(*it,*it);
}
int rt[N];
namespace seg_tree{
    #define ls e[rt].ch[0]
    #define rs e[rt].ch[1]
    struct node {
        int ch[2],ma,tot;
    }e[N*42];
    int cnt;
    void pushup(int rt) {
        e[rt].ma=max(e[ls].ma,e[rs].ma);
        e[rt].tot=e[ls].tot+e[rs].tot;
    }
    void insert(int &rt,int L,int k,int l,int r) {
        if(!rt) rt=++cnt;
        if(l==r) {e[rt].ma=e[rt].tot=k;return;}
        int mid=(l+r)>>1;
        if(L<=mid) insert(ls,L,k,l,mid);
        else insert(rs,L,k,mid+1,r);
        pushup(rt);
    }
    int query_max(int L,int R,int l,int r,int rt) {
        if(!rt) return 0;
        if(L<=l&&r<=R) return e[rt].ma;
        int mid=(l+r)>>1,ans=0;
        if(L<=mid) ans=max(ans,query_max(L,R,l,mid,ls));
        if(R>mid) ans=max(ans,query_max(L,R,mid+1,r,rs));
        return ans;
    }
    int query_tot(int L,int R,int l,int r,int rt) {
        if(!rt) return 0;
        if(L<=l&&r<=R) return e[rt].tot;
        int mid=(l+r)>>1,ans=0;
        if(L<=mid) ans+=query_tot(L,R,l,mid,ls);
        if(R>mid) ans+=query_tot(L,R,mid+1,r,rs);
        return ans;
    }
}
int Query_Sum(int x,int y) {
    int ans=0,tmp=xy[x];
    while(top[x]!=top[y]) {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans+=seg_tree::query_tot(idx[top[x]],idx[x],1,n,rt[tmp]);
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    ans+=seg_tree::query_tot(idx[x],idx[y],1,n,rt[tmp]);
    return ans;
}
int Query_Max(int x,int y) {
    int ans=0,tmp=xy[x];
    while(top[x]!=top[y]) {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans=max(seg_tree::query_max(idx[top[x]],idx[x],1,n,rt[tmp]),ans);
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    ans=max(seg_tree::query_max(idx[x],idx[y],1,n,rt[tmp]),ans);
    return ans;
}
int main() {
    n=read(),m=read();
    FOR(i,1,n) pj[i]=read(),xy[i]=read();
    FOR(i,2,n) {
        int x=read(),y=read();
        G[x].push_back(y),G[y].push_back(x);
    }
    dfs1(1,0);
    dfs2(1,1);
    FOR(i,1,n) seg_tree::insert(rt[xy[i]],idx[i],pj[i],1,n);
    FOR(i,1,m) {
        char s[10];
        scanf("%s",s);
        int x=read(),y=read();
        if(s[0]=='C'&&s[1]=='C') {
            seg_tree::insert(rt[xy[x]],idx[x],0,1,n);
            xy[x]=y;
            seg_tree::insert(rt[xy[x]],idx[x],pj[x],1,n);
        } else if(s[0]=='C'&&s[1]=='W') {
            pj[x]=y;
            seg_tree::insert(rt[xy[x]],idx[x],pj[x],1,n);
        } else if(s[0]=='Q'&&s[1]=='S') {
            printf("%d
",Query_Sum(x,y));
        } else {//OK
            printf("%d
",Query_Max(x,y));
        }
    }
    return 0;
}