bzoj 4196 [Noi2015]软件包管理器 (树链剖分+线段树）

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define mid int m = (l + r) >> 1
const int mod = 201314;
const int M = 2e5 + 10;  //建了双向边 *个2
struct node{
    int to,next;
}e[M];
int cnt,cnt1,n;
int son[M],siz[M],head[M],fa[M],top[M],dep[M],tid[M],mx[M],rk[M];
int sum[M<<2],lazy[M<<2];
void add(int u,int v){
    e[++cnt].to = v;e[cnt].next = head[u];head[u] = cnt;
}

void dfs1(int u,int faz,int deep){
    dep[u] = deep;
    fa[u] = faz;
    siz[u] = 1;
    for(int i = head[u];i;i = e[i].next){
        int v = e[i].to;
        if(v == faz) continue;
        dfs1(v,u,deep+1);
        siz[u] += siz[v];
        if(siz[v] > siz[son[u]]||son[u] == -1)
            son[u] = v;
    }
}

void dfs2(int u,int t){
    top[u] = t;
    mx[u] = cnt1;
    tid[u] = cnt1;
    rk[cnt1] = u;
    cnt1++;
    if(son[u] == -1) return ;
    dfs2(son[u],t),mx[u] = max(mx[u],mx[son[u]]);
    for(int i = head[u];i;i=e[i].next){
        int v = e[i].to;
        if(v != fa[u]&&v != son[u])
            dfs2(v,v),mx[u] = max(mx[u],mx[v]);
    }
}

void pushup(int rt){
    sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}

void pushdown(int l,int r,int rt){
    if(lazy[rt]==0){
        sum[rt<<1] = sum[rt<<1|1] = 0;
        lazy[rt<<1] = lazy[rt<<1|1] = 0;
        lazy[rt] = -1;
    }
    else if(lazy[rt] == 1){
        mid;
        sum[rt<<1] = m-l+1  ;
        sum[rt<<1|1] = r-m;
        lazy[rt<<1] = lazy[rt<<1|1] = 1;
        lazy[rt] = -1;
    }
}

void build(int l,int r,int rt){
    lazy[rt] = -1;
    if(l == r){
        sum[rt] = 0;
        lazy[rt] = -1;
        return ;
    }
    mid;
    build(lson); build(rson);
}

int update(int L,int R,int c,int l,int r,int rt){
   if(L <= l&&R >= r){
       if(c==0){
           int cnt = sum[rt];
           sum[rt] = 0; lazy[rt] = 0;
           return cnt;
       }
       else{
            int cnt = r-l+1-sum[rt];
            sum[rt] = r-l+1;
            lazy[rt] = 1;
            return cnt;
       }
   }
   pushdown(l,r,rt);
   mid; int ret = 0;
   if(L <= m) ret += update(L,R,c,lson);
   if(R > m) ret += update(L,R,c,rson);
   pushup(rt);
   return ret;
}

int solve(int x,int y){
    int fx = top[x],fy = top[y];
    int ans = 0;
    while(fx != fy){
        if(dep[fx] < dep[fy]) swap(fx,fy),swap(x,y);
        ans += update(tid[fx],tid[x],1,1,n,1);
        x = fa[fx]; fx = top[x];
    }
    if(dep[x] > dep[y]) swap(x,y);
    ans += update(tid[x],tid[y],1,1,n,1);
    return ans;
}

char s[100];
int main()
{
    int x,m;
    cnt = 1,cnt1 = 1;
    scanf("%d",&n);
    memset(son,-1,sizeof(son));
    for(int i = 2;i <= n;i ++){
        scanf("%d",&x);
        add(x+1,i);add(i,x+1);
    }
    dfs1(1,0,1); dfs2(1,0);
    build(1,n,1);
    scanf("%d",&m);
    for(int i = 1;i <= m;i ++){
        scanf("%s",s);
        if(s[0] == ‘i‘){
            scanf("%d",&x);
            x++;
            printf("%d\n",solve(x,1));
        }
        else{
            scanf("%d",&x);
            x++;
            printf("%d\n",update(tid[x],mx[x],0,1,n,1));
        }
    }
    return 0;
}