Submission #74291

#	Time	Username	Problem	Language	Result	Execution time	Memory
74291		Bruteforceman	Regions (IOI09_regions)	C++11	100 / 100	6595 ms	75512 KiB

regions

#include "bits/stdc++.h"
using namespace std;
int N, R, Q;
int a[200010], p[200010];
const int magic = 200;
const int chunk = 5 + (200000 / magic);
int ans[chunk][25001];
vector <int> g[200010];

int idx[25001];
int current;
int tot[25001];

void dfs(int x, int cnt) {
	cnt += (current == a[x]);
	if(a[x] != current) {
		ans[idx[current]][a[x]] += cnt;
	}
	for(auto i : g[x]) {
		dfs(i, cnt);
	}
} 

int in[200010];
int out[200010];
vector <int> v[25001];
vector <int> nodes[25001];
int cur;

void go(int x) {
	in[x] = ++cur;
	v[a[x]].emplace_back(in[x]);
	for(auto i : g[x]) {
		go(i);
	}
	out[x] = cur;
}
int count(int l, int r, int val) {
	return upper_bound(v[val].begin(), v[val].end(), r) - lower_bound(v[val].begin(), v[val].end(), l);
}

int main(int argc, char const *argv[])
{
	scanf("%d %d %d", &N, &R, &Q);
	for(int i = 1; i <= N; i++) {
		if(i == 1) scanf("%d", &a[i]);
		else scanf("%d %d", &p[i], &a[i]);
	}
	for(int i = 2; i <= N; i++) {
		g[p[i]].emplace_back(i);
	}
	for(int i = 1; i <= N; i++) {
		tot[a[i]] += 1;
		nodes[a[i]].emplace_back(i);
	}
	int now = 0;
	for(int i = 1; i <= R; i++) {
		if(tot[i] > magic) {
			current = i;
			idx[i] = now++; 
			dfs(1, 0);
		}
	}
	go(1);
	while(Q--) {
		int p, q;
		scanf("%d %d", &p, &q);
		if(tot[p] > magic) {
			printf("%d\n", ans[idx[p]][q]);
		} else {
			int res = 0;
			for(int i : nodes[p]) {
				res += count(in[i], out[i], q);
			}
			printf("%d\n", res);
		}
		fflush(stdout);
	}
	return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main(int, const char**)':
regions.cpp:44:7: 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:46:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   if(i == 1) scanf("%d", &a[i]);
              ~~~~~^~~~~~~~~~~~~
regions.cpp:47:13: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   else scanf("%d %d", &p[i], &a[i]);
        ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &p, &q);
   ~~~~~^~~~~~~~~~~~~~~~~

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