/*
* Flatten the tree using Euler tour, note the end points of subtree of each node in tin[] and tout[].
* Maintain the nodes in each region. Also keep a sorted list of tin[] of the nodes in each region.
* For query (r1, r2), for each node 'i' in r1, binary search for the number of nodes in region r2 with tin[] between [tin[i]+1, tout[i]]. Add them all up to get the answer.
*
* This works within the time limit because of the fact that there can only be a small amount of distinct regions queries (R * (R+1) / 2).
* This means that there are a lot of repeated queries. Sadly, we cannot use a R*R array for keeping track of answers (MLE).
* We use a gp_hash_table to keep track of the queries and their answers. If repeated, we just answer in constant time.
* unordered_map usually missed one test case when I tried, so gets 95.
* gp_hash_table gets 100.
*/
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#include <bits/stdc++.h>
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
//#define endl '\n'
const int MXN = 200000, MXR = 25000, INF = 1e9+1, k = 1000;
int n, r, q;
int reg[MXN+1], tin[MXN+1], tout[MXN+1], pt = 0;
vi adj[MXN+1];
vi regList[MXR+1], regListId[MXR+1];
gp_hash_table<int, int> seen[MXR+1];
void dfs(int p, int parent) {
regList[reg[p]].push_back(pt);
regListId[reg[p]].push_back(p);
tin[p] = pt++;
for (int i: adj[p]) if (i != parent) dfs(i, p);
tout[p] = pt-1;
}
int main() {
#ifdef shiven
freopen("test.in", "r", stdin);
#endif
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> r >> q;
cin >> reg[0];
reg[0] -= 1;
for_(i, 1, n) {
int p; cin >> p >> reg[i];
reg[i] -= 1;
adj[p-1].push_back(i);
}
dfs(0, 0);
while (q--) {
int r1, r2; cin >> r1 >> r2;
r1 -= 1; r2 -= 1;
if (seen[r1].find(r2) != seen[r1].end()) {
cout << seen[r1][r2] << endl;
continue;
}
int ans = 0;
for (auto i: regListId[r1])
ans += upper_bound(regList[r2].begin(), regList[r2].end(), tout[i]) - lower_bound(regList[r2].begin(), regList[r2].end(), tin[i]+1);
cout << ans << endl;
seen[r1][r2] = ans;
if (seen[r1].size() >= k) seen[r1].clear();
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
10 ms |
11520 KB |
Output is correct |
| 2 |
Correct |
12 ms |
11520 KB |
Output is correct |
| 3 |
Correct |
12 ms |
11520 KB |
Output is correct |
| 4 |
Correct |
12 ms |
11564 KB |
Output is correct |
| 5 |
Correct |
16 ms |
11596 KB |
Output is correct |
| 6 |
Correct |
31 ms |
11648 KB |
Output is correct |
| 7 |
Correct |
40 ms |
11648 KB |
Output is correct |
| 8 |
Correct |
47 ms |
11768 KB |
Output is correct |
| 9 |
Correct |
71 ms |
12280 KB |
Output is correct |
| 10 |
Correct |
102 ms |
12256 KB |
Output is correct |
| 11 |
Correct |
137 ms |
12664 KB |
Output is correct |
| 12 |
Correct |
207 ms |
13180 KB |
Output is correct |
| 13 |
Correct |
178 ms |
13024 KB |
Output is correct |
| 14 |
Correct |
281 ms |
13560 KB |
Output is correct |
| 15 |
Correct |
344 ms |
16296 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1543 ms |
17416 KB |
Output is correct |
| 2 |
Correct |
1855 ms |
16116 KB |
Output is correct |
| 3 |
Correct |
2777 ms |
19868 KB |
Output is correct |
| 4 |
Correct |
416 ms |
14092 KB |
Output is correct |
| 5 |
Correct |
413 ms |
16140 KB |
Output is correct |
| 6 |
Correct |
678 ms |
15448 KB |
Output is correct |
| 7 |
Correct |
1000 ms |
15944 KB |
Output is correct |
| 8 |
Correct |
1547 ms |
22832 KB |
Output is correct |
| 9 |
Correct |
2892 ms |
25692 KB |
Output is correct |
| 10 |
Correct |
5643 ms |
32068 KB |
Output is correct |
| 11 |
Correct |
4919 ms |
26480 KB |
Output is correct |
| 12 |
Correct |
5862 ms |
23824 KB |
Output is correct |
| 13 |
Correct |
6466 ms |
24724 KB |
Output is correct |
| 14 |
Execution timed out |
8055 ms |
25040 KB |
Time limit exceeded |
| 15 |
Execution timed out |
8079 ms |
30668 KB |
Time limit exceeded |
| 16 |
Execution timed out |
8022 ms |
35468 KB |
Time limit exceeded |
| 17 |
Correct |
7539 ms |
35324 KB |
Output is correct |
