Submission #53628

#	Time	Username	Problem	Language	Result	Execution time	Memory
53628		baactree	Regions (IOI09_regions)	C++17	3 / 100	8069 ms	75436 KiB

regions

#include <bits/stdc++.h>
using namespace std;
int n, r, q;
vector<int> adj[200005];
int arr[200005];
const int sz = 467;
int dp[sz][25005];
pair<int,int> cnt[25005];
int inv[25005];
int le[200005], ri[200005];
vector<int> idx[25005];
vector<pair<int, int> > vec[25005];
int vn;
void dfs(int now, int par) {
	idx[arr[now]].push_back(vn);
	le[now] = vn++;
	for (auto &there : adj[now]) {
		if (there == par)continue;
		dfs(there, now);
	}
	ri[now] = vn++;
	vec[arr[now]].emplace_back(le[now], ri[now]);
}
int main() {
	scanf("%d%d%d", &n, &r, &q);
	scanf("%d", &arr[1]);
	cnt[arr[1]].first++;
	for (int i = 2; i <= n; i++) {
		int a, b;
		scanf("%d%d", &a, &b);
		adj[a].push_back(i);
		adj[i].push_back(a);
		arr[i] = b;
		cnt[arr[i]].first++;
	}
	for (int i = 0; i < 25005; i++)
		cnt[i].second = i;
	sort(cnt, cnt + 25005, [&](pair<int, int> &a, pair<int, int> &b) {
		return a > b;
	});
	for (int i = 0; i < 25005; i++)
		inv[cnt[i].second] = i;
	dfs(1, 0);
	for (int i = 0; i < 25005; i++)
		sort(vec[i].begin(), vec[i].end());
	for (int i = 0; i < sz; i++) {
		int a = cnt[i].second;
		for (int b = 1; b <= r; b++) {
			int ans = 0;
			int lidx = 0, ridx = 0;
			for (auto x : vec[a]) {
				int le = x.first;
				int ri = x.second;
				while (lidx < idx[b].size() && idx[b][lidx] < le)lidx++;
				while (ridx < idx[b].size() && idx[b][ridx] <= ri)ridx++;
				ans += ridx - lidx;
			}
			dp[i][b] = ans;
		}
	}
	while (q--) {
		int a, b;
		scanf("%d%d", &a, &b);
		if (inv[a] < sz) {
			printf("%d\n", dp[inv[a]][b]);
			fflush(stdout);
		}
		else {
			int ans = 0;
			for (auto x : vec[a]) {
				int le = x.first;
				int ri = x.second;
				ans += upper_bound(idx[b].begin(), idx[b].end(), ri) - lower_bound(idx[b].begin(), idx[b].end(), le);
			}
			printf("%d\n", ans);
			fflush(stdout);
		}
	}
	return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:54:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (lidx < idx[b].size() && idx[b][lidx] < le)lidx++;
            ~~~~~^~~~~~~~~~~~~~~
regions.cpp:55:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (ridx < idx[b].size() && idx[b][ridx] <= ri)ridx++;
            ~~~~~^~~~~~~~~~~~~~~
regions.cpp:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &n, &r, &q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
regions.cpp:26:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &arr[1]);
  ~~~~~^~~~~~~~~~~~~~~
regions.cpp:30:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~
regions.cpp:63:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 3 / 15
• Subtask 2: 0 / 85