bzoj4999 This Problem Is Too Simple！（树链剖分+动态开点线段树）

对每一个权值开一棵线段树，维护区间和。空间不够，要动态开点。

#include <bits/stdc++.h>using namespace std;#define N 100010inline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();    return x*f;}int n,m,a[N],h[N],num=0,cnt=0,tot=0,root[300010];int dep[N],fa[N],son[N],size[N],id[N],dfn=0,top[N];map<int,int>mp;struct edge{    int to,next;}data[N<<1];inline void add(int x,int y){    data[++num].to=y;data[num].next=h[x];h[x]=num;}struct node{    int lc,rc,sum;}tree[4000010];void dfs1(int x){    size[x]=1;    for(int i=h[x];i;i=data[i].next){        int y=data[i].to;        if(y==fa[x]) continue;        fa[y]=x;dep[y]=dep[x]+1;dfs1(y);size[x]+=size[y];        if(size[y]>size[son[x]]) son[x]=y;    }}void dfs2(int x,int tp){    id[x]=++dfn;top[x]=tp;    if(son[x]) dfs2(son[x],tp);    for(int i=h[x];i;i=data[i].next){        int y=data[i].to;        if(y==fa[x]||y==son[x]) continue;        dfs2(y,y);    }}inline void pushup(int p){    tree[p].sum=tree[tree[p].lc].sum+tree[tree[p].rc].sum;}void add1(int &p,int l,int r,int x,int val){    if(!p) p=++cnt;    if(l==r){tree[p].sum+=val;return;}    int mid=l+r>>1;    if(x<=mid) add1(tree[p].lc,l,mid,x,val);    else add1(tree[p].rc,mid+1,r,x,val);    pushup(p);}int qsum(int p,int l,int r,int x,int y){    if(!p) return 0;    if(x<=l&&r<=y) return tree[p].sum;    int mid=l+r>>1,res=0;    if(x<=mid) res+=qsum(tree[p].lc,l,mid,x,y);    if(y>mid) res+=qsum(tree[p].rc,mid+1,r,x,y);    return res;}int solve(int x,int y,int val){    if(!mp[val]) return 0;int res=0;    while(top[x]!=top[y]){        if(dep[top[x]]<dep[top[y]]) swap(x,y);        res+=qsum(root[mp[val]],1,n,id[top[x]],id[x]);        x=fa[top[x]];    }    if(id[x]>id[y]) swap(x,y);    return res+qsum(root[mp[val]],1,n,id[x],id[y]);}int main(){//  freopen("a.in","r",stdin);    n=read();m=read();    for(int i=1;i<=n;++i) a[i]=read();    for(int i=1;i<n;++i){        int x=read(),y=read();add(x,y);add(y,x);    }dep[1]=1;dfs1(1);dfs2(1,1);    for(int i=1;i<=n;++i){        if(!mp[a[i]]) mp[a[i]]=++tot;        add1(root[mp[a[i]]],1,n,id[i],1);    }    while(m--){        char op[1];scanf("%s",op);int x=read(),y=read();        if(op[0]=='C'){            add1(root[mp[a[x]]],1,n,id[x],-1);a[x]=y;            if(!mp[a[x]]) mp[a[x]]=++tot;            add1(root[mp[a[x]]],1,n,id[x],1);        }        else printf("%d\n",solve(x,y,read()));    }    return 0;}