POJ-3321

POJ-3321
大佬的博客

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;
#define ll long long
const int maxn = 1e5 + 10;
int n, trans[maxn];
//避免超时，用了vector + vector;不能用vector<maxn>
vector<vector<int> > v(maxn);
int tree[maxn];
int apple[maxn];
int Next[maxn];
int cnt = 1;

inline int lowbit(int x) { return x&(-x); }

void add(int x, int num) { for (int i = x; i <= n; i += lowbit(i)) tree[i] += num; }

ll getsum(int x) {
    ll ans = 0;
    for (int i = x; i > 0; i -= lowbit(i)) ans += tree[i];
    return ans;
}

void dfs(int x) {
    trans[x] = cnt++;
    for (int i = 0; i < v[x].size(); i++) dfs(v[x][i]);
    Next[trans[x]] = cnt - 1;
}

int main() {
    //freopen("in","r",stdin);
    while (scanf("%d", &n) !=EOF && n) {
        int a, b;
        cnt = 1;
        memset(tree, 0, sizeof(tree));
        memset(Next, 0, sizeof(Next));
        memset(trans, 0, sizeof(trans));
        for (int i = 1; i <= n; i++) {
            v[i].clear();
            apple[i] = 1;
            add(i, 1);
        }
        for (int i = 1; i < n; i++) {
            scanf("%d %d", &a, &b);
            v[a].push_back(b);
        }
        dfs(1);
        int T;
        scanf("%d", &T);
        while (T--) {
            char s[4];
            int k;

            scanf("%s %d",s,&k);
            int t = trans[k];
            if (s[0] == 'Q') {
                ll t1 = getsum(Next[t]);
                ll t2 = getsum(t - 1);
                printf("%lld
", getsum(Next[t]) - getsum(t - 1));
            } else {
                if (apple[k] == 1)
                    add(t, -1);
                else add(t, 1);
                apple[k] = !apple[k];
            }
        }
    }

    return 0;
}