BZOJ4999 樹剖+動態開點

表示只會樹剖 對於每個新點 動態開線段樹就好了

#include<bits/stdc++.h>
#define N 100010
#define lson l , mid , ls[x]
#define rson mid + 1 , r , rs[x]
using namespace std;
map<int , int> mp;
int a[N] , head[N] , to[N << 1] , next[N << 1] , cnt , fa[N] , deep[N] , si[N] , bl[N] , pos[N] , num;
int root[N << 2] , ls[N << 7] , rs[N << 7] , sum[N << 7] , tot , n , clo;
char str[5];
void add(int x , int y) {
    to[++cnt] = y , next[cnt] = head[x] , head[x] = cnt;
}
void dfs1(int x) {
    int i;
    si[x] = 1;
    for(i = head[x] ; i ; i = next[i])
        if(to[i] != fa[x])
            fa[to[i]] = x , deep[to[i]] = deep[x] + 1 , dfs1(to[i]) , si[x] += si[to[i]];
}
void dfs2(int x , int c) {
    int i , k = 0;
    bl[x] = c , pos[x] = ++num;
    for(i = head[x] ; i ; i = next[i])
        if(to[i] != fa[x] && si[to[i]] > si[k])
            k = to[i];
    if(k) {
        dfs2(k , c);
        for(i = head[x] ; i ; i = next[i])
            if(to[i] != fa[x] && to[i] != k)
                dfs2(to[i] , to[i]);
    }
}
void update(int p , int a , int l , int r , int &x) {
    if(!x) x = ++tot;
    sum[x] += a;
    if(l == r) return;
    int mid = (l + r) >> 1;
    if(p <= mid) update(p , a , lson);
    else update(p , a , rson);
}
int query(int b , int e , int l , int r , int x) {
    if(!x) return 0;
    if(b <= l && r <= e) return sum[x];
    int mid = (l + r) >> 1 , ans = 0;
    if(b <= mid) ans += query(b , e , lson);
    if(e > mid) ans += query(b , e , rson);
    return ans;
}
int solve(int x , int y , int c) {
    int ans = 0;
    while(bl[x] != bl[y]) {
        if(deep[bl[x]] < deep[bl[y]]) swap(x , y);
        ans += query(pos[bl[x]] , pos[x] , 1 , n , root[c]) , x = fa[bl[x]];
    }
    if(deep[x] > deep[y]) swap(x , y);
    ans += query(pos[x] , pos[y] , 1 , n , root[c]);
    return ans;
}
int main() {
    int m , i , x , y , z;
    scanf("%d%d" , &n , &m);
    for(i = 1 ; i <= n ; i ++ ) scanf("%d" , &a[i]);
    for(i = 1 ; i < n ; i ++ ) scanf("%d%d" , &x , &y) , add(x , y) , add(y , x);
    dfs1(1) , dfs2(1 , 1);
    for(i = 1 ; i <= n ; i ++ ) {
        if(!mp[a[i]]) mp[a[i]] = ++clo;
        update(pos[i] , 1 , 1 , n , root[mp[a[i]]]);
    }
    while(m -- ) {
        scanf("%s%d%d" , str , &x , &y);
        if(str[0] == 'C') {
            update(pos[x] , -1 , 1 , n , root[mp[a[x]]]);
            if(!mp[y]) mp[y] = ++clo;
            update(pos[x] , 1 , 1 , n , root[mp[y]]);
            a[x] = y;
        } else {
            scanf("%d" , &z);
            if(!mp[z]) puts("0");
            else printf("%d\n" , solve(x , y , mp[z]));
        }
    }
    return 0;
}