【NOI 2015】软件包管理器

【题目链接】

点击打开链接

【算法】

树链剖分，子树的DFS序也是连续的一段

要注意细节！

【代码】

#include<bits/stdc++.h>
using namespace std;
#define MAXN 100000

struct SegmentTree {
    int l,r,sum[],opt;
} tree[MAXN*];

int i,N,Q,x,num;
int depth[MAXN+],size[MAXN+],son[MAXN+],fa[MAXN+],
    top[MAXN+],id[MAXN+];
string type;
vector<int> E[MAXN+];

template <typename T> inline void read(T &x) {
    int f = ; x = ;
    char c = getchar();
    for (; !isdigit(c); c = getchar()) { if (c == '-') f = -f; }
    for (; isdigit(c); c = getchar()) x = x *  + c - '';
    x *= f;
}

template <typename T> inline void write(T x) {
    if (x < ) { putchar('-'); x = -x; }
    if (x > ) write(x/);
    putchar(x%+'');
}

template <typename T> inline void writeln(T x) {
    write(x);
    puts("");
}

inline void dfs1(int x) {
    int i,y;
    size[x] = ;
    for (i = ; i < E[x].size(); i++) {
        y = E[x][i];
        if (y != fa[x]) {
            fa[y] = x;
            depth[y] = depth[x] + ;
            dfs1(y);
            size[x] += size[y];
            if ((size[y] > size[son[x]]) || (!son[x])) son[x] = y;
        }
    }
}

inline void dfs2(int x,int tp) {
    int i,y;
    top[x] = tp; id[x] = ++num;
    if (son[x]) dfs2(son[x],tp);
    for (i = ; i < E[x].size(); i++) {
        y = E[x][i];
        if ((y != fa[x]) && (y != son[x]))
            dfs2(y,y);
    }
}

inline void build(int index,int l,int r) {
    int mid;
    tree[index].l = l; tree[index].r = r;
    tree[index].opt = ;
    tree[index].sum[] = r - l + ;
    if (l == r) return;
    mid = (l + r) >> ;
    build(index*,l,mid); build(index*+,mid+,r);
}

inline void pushdown(int index) {
    if (tree[index].l == tree[index].r) return;
    tree[index*].opt = tree[index].opt;
    tree[index*].sum[tree[index].opt] = tree[index*].r - tree[index*].l + ;
    tree[index*].sum[tree[index].opt^] = ;
    tree[index*+].opt = tree[index].opt;
    tree[index*+].sum[tree[index].opt] = tree[index*+].r - tree[index*+].l + ;
    tree[index*+].sum[tree[index].opt^] = ;
}

inline void pushup(int index) {
    tree[index].sum[] = tree[index*].sum[] + tree[index*+].sum[];
    tree[index].sum[] = tree[index*].sum[] + tree[index*+].sum[];
    if (tree[index*].opt != tree[index*+].opt) {
        tree[index].opt = -;
        return;
    }
    if ((tree[index*].opt == -) || (tree[index*+].opt == -)) {
        tree[index].opt = -;
        return;
    }
    tree[index].opt = tree[index*].opt;
}

void modify(int index,int l,int r,int val) {
    int mid;
    if (tree[index].opt != -) pushdown(index);
    if ((tree[index].l == l) && (tree[index].r == r)) {
        tree[index].sum[val] = r - l + ;
        tree[index].sum[val^] = ;
        tree[index].opt = val;
    } else {
        mid = (tree[index].l + tree[index].r) >> ;
        if (mid >= r) modify(index*,l,r,val);
        else if (mid +  <= l) modify(index*+,l,r,val);
        else {
            modify(index*,l,mid,val);
            modify(index*+,mid+,r,val);
        }
        pushup(index);
    }
}

inline int query(int index,int l,int r,int val) {
    int mid;
    if (tree[index].opt != -) pushdown(index);
    if ((tree[index].l == l) && (tree[index].r == r)) return tree[index].sum[val];
    else {
        mid = (tree[index].l + tree[index].r) >> ;
        if (mid >= r) return query(index*,l,r,val);
        else if (mid +  <= l) return query(index*+,l,r,val);
        else return query(index*,l,mid,val) + query(index*+,mid+,r,val);
    }
}

inline int Install(int x) {
    int tp = top[x],
        ans = ;
    while (tp) {
        ans += query(,id[tp],id[x],);
        modify(,id[tp],id[x],);
        x = fa[tp]; tp = top[x];
    }
    ans += query(,,id[x],);
    modify(,,id[x],);
    return ans;
} 

inline int Uninstall(int x) {
     int ans = query(,id[x],id[x]+size[x]-,);
    modify(,id[x],id[x]+size[x]-,);
    return ans;
}

int main() {

    read(N); 

    for (i = ; i < N; i++) {
        read(x);
        E[x].push_back(i);
    }

    depth[] = ;
    dfs1();
    dfs2(,);

    build(,,num);

    read(Q);
    while (Q--) {
        cin >> type;
        if (type == "install") {
            read(x);
            writeln(Install(x));
        } else {
            read(x);
            writeln(Uninstall(x));
        }
    }

    return ;
}