hdu 4358 Boring counting

题意：给出一棵树，每个点有一个点权，问一x为根的子树中有多少种权重恰好出现了k次。

懒了，直接贴题解，况且本来也不是自己写出来的

#include <cstdio>#include <cstring>#include <algorithm>#include<cmath>#include<map>using namespace std;const int maxn = 100010;struct node {int be, ne;void init(int b, int e) {be = b;ne = e;}} buf[maxn * 2];struct query {int id, from, to;bool operator <(const query &oth) const {return to < oth.to;}} qq[maxn];int E[maxn], len;void add(int a, int b) {buf[len].init(b, E[a]);E[a] = len++;buf[len].init(a, E[b]);E[b] = len++;}int cnt, id[maxn];int ss[maxn];int color[maxn], ans[maxn], cas, n, k, a, b, m;map<int, int> mp;int head[maxn], nxt[maxn], last[maxn], num[maxn];void init(int n) {for (int i = 1; i <= n; i++) {E[i] = -1;qq[i].from = qq[i].to = 0;qq[i].id = i;ss[i] = num[i] = head[i] = 0;}mp.clear();len = 0;cnt = 0;}void dfs(int a) {qq[a].from = qq[a].to = ++cnt;id[cnt] = a;for (int i = E[a]; i != -1; i = buf[i].ne) {int b = buf[i].be;if (qq[b].from)continue;dfs(b);qq[a].to = qq[b].to;}}int lowbit(int k) {return (k & -k);}void inc(int i, int k) {while (i <= n) {ss[i] += k;i += lowbit(i);}}int get(int i) {int res = 0;while (i > 0) {res += ss[i];i -= lowbit(i);}return res;}void update(int from, int to, int v) {inc(from, v);inc(to + 1, -v);}int main() {scanf("%d", &cas);for (int c = 1; c <= cas; c++) {printf("Case #%d:\n", c);scanf("%d%d", &n, &k);init(n);for (int i = 1; i <= n; i++) {scanf("%d", color + i);mp[color[i]] = 0;}int cnt = 0;for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)(*it).second = ++cnt;for (int i = 1; i <= n; i++)color[i] = mp[color[i]];for (int i = 1; i < n; i++) {scanf("%d %d", &a, &b);add(a, b);}dfs(1);sort(qq + 1, qq + n + 1);int p = 0;for (int i = 1; i <= n; i++) {while (p < qq[i].to) {p++;int t = color[id[p]];num[t]++;nxt[last[t]] = p;last[t] = p;if (head[t] == 0)head[t] = p;if (num[t] == k)update(1, head[t], 1);if (num[t] == k + 1) {update(1, head[t], -1);update(head[t] + 1, nxt[head[t]], 1);}if (num[t] > k + 1) {update(head[t] + 1, nxt[head[t]], -1);head[t] = nxt[head[t]];update(head[t] + 1, nxt[head[t]], 1);}}ans[qq[i].id] = get(qq[i].from);}scanf("%d", &m);while (m--) {scanf("%d", &a);printf("%d\n", ans[a]);}if (c != cas)printf("\n");}return 0;}