bzoj 4196：[NOI2015] 软件包管理器 （树链剖分）

第一次做树剖

找同学要了模板 + 各种借鉴

先用dfs在划分轻重链并编号， install的时候就从查询的节点到根寻找标记的点有多少个，再用深度减去标记的点的个数，并把路径上所有点都标记

uninstall就是搜索查询的点的子树的标记个数，并取消所有的标记。

代码如下

 /**************************************************************
     Problem: 4196
     Language: C++
     Result: Accepted
     Time:8312 ms
     Memory:7416 kb
 ****************************************************************/

 #include <cstdio>
 #include <vector>
 #include <cstring>
 using namespace std;
 #define g(l, r) (l + r | l != r)
 #define o g(l, r)
 #define ls g(l, mid)
 #define rs g(mid + 1, r)
 const int N = ; 

 int n, dep[N], fa[N], hs[N], size[N], top[N], pos[N], mark[N<<], sum[N<<], tot, L, R, m;
 vector < int > edge[N];

 inline void dfs1(int u, int d, int f){
     dep[u] = d; fa[u] = f;  hs[u] = -;  size[u] = ;
     int tmp = ;
     for (int i = ; i < edge[u].size(); i++){
         int &v = edge[u][i];
         dfs1(v, d + , u);
         if (size[v] > tmp)
             hs[u] = v, tmp = size[v];
         size[u] += size[v];
     }
 }

 inline void dfs2(int u, int T){
     top[u] = T; pos[u] = ++tot;
     if (hs[u] == -)    return ;
     dfs2(hs[u], T);
     for (int i = ; i < edge[u].size(); i++){
         int &v = edge[u][i];
         if (hs[u] == v) continue;
         dfs2(v, v);
     }
 }

 inline void push(int l, int r) {
     if (mark[o] == -) return;
     int mid = l + r >> ;
     if (l < r) {
         mark[ls] = mark[o];
         sum[ls] = mark[o] * (mid - l  + );
         mark[rs] = mark[o];
         sum[rs] = mark[o] * (r - (mid + ) + );
     }
     mark[o] = -;
 }

 void modify(int l, int r){
     if (L <= l && r <= R){
         sum[o] = m * (r - l + );
         mark[o] = m;
         return ;
     }
     push(l, r);
     int mid = l + r >> ;
     if (L <= mid)    modify(l, mid);
     if (R >= mid + )    modify(mid + , r);
     sum[o] = sum[ls] + sum[rs];
 }

 int getSum(int l, int r){
     if (L <= l && r <= R){
         return sum[o];
     }
     push(l, r);
     int mid = l + r >> , ans = ;
     if (L <= mid)    ans += getSum(l, mid);
     if (R >= mid + )    ans += getSum(mid + , r);
     return ans;
 }

 inline void install(int u){
     int f = top[u], ans = dep[u];
     m = ;
     while(f){
         L = pos[f], R = pos[u];
         ans -= getSum(, tot);
         modify(, tot);
         u = fa[f]; f = top[u];
     }
     L = pos[f], R = pos[u];
     ans -= getSum(, tot);
     modify(, tot);
     printf("%d\n", ans);
 }

 inline void uninstall(int u){
     L = pos[u], R = pos[u] + size[u] - , m = ;
     int ans = getSum(, tot);
     modify(, tot);
     printf("%d\n", ans);
 }

 int main(){
     scanf("%d", &n);
     for (int i = ; i < n; i++){
         int x; scanf("%d", &x);
         edge[x].push_back(i);
     }
     dfs1(, , -);  dfs2(, );
     int q;
     scanf("%d", &q);
     memset(mark, 0xff, sizeof(mark));
     while(q--){
         char str[]; int x;
         scanf("%s%d", str, &x);
         if (*str == 'i')    install(x);
         else uninstall(x);
     }
     return ;
 }