#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = array<int, 2>;
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
template<class T> bool smax(T &a, T b) {
return a < b ? a = b, 1 : 0;
}
template<class T> bool smin(T &a, T b) {
return a > b ? a = b, 1 : 0;
}
void solve() {
int n, r, q;
cin >> n >> r >> q;
vector<int> reg(n);
cin >> reg[0], --reg[0];
vector<vector<int>> adj(n);
for (int i = 1; i < n; i++) {
int p, h; cin >> p >> h;
adj[--p].push_back(i);
reg[i] = --h;
}
const int b = sqrt(n);
vector<int> tin(n), tout(n), mp(n);
vector<vector<int>> comp(r);
int timer = 0;
auto tour = [&](int u, auto&& tour) -> void {
tin[u] = timer++, mp[tin[u]] = u;
comp[reg[u]].push_back(tin[u]);
for (int v : adj[u]) {
tour(v, tour);
}
tout[u] = timer;
}; tour(0, tour);
vector<vector<int>> calc;
vector<int> id(r, -1);
auto dfs = [&](int u, int e1, int tot,
auto&& dfs) -> void {
if (reg[u] == e1) ++tot;
calc[id[e1]][reg[u]] += tot;
for (int v : adj[u]) {
dfs(v, e1, tot, dfs);
}
};
int run = 0;
for (int i = 0; i < r; i++) {
if (sz(comp[i]) >= b) {
id[i] = run++;
calc.push_back(vector<int>(r));
dfs(0, i, 0, dfs);
}
}
while (q--) {
int e1, e2;
cin >> e1 >> e2;
--e1, --e2;
if (sz(comp[e1]) >= b) {
cout << calc[id[e1]][e2] << "\n";
} else {
int tot = 0;
for (int u : comp[e1]) {
tot += lower_bound(all(comp[e2]), tout[mp[u]])
- lower_bound(all(comp[e2]), tin[mp[u]]);
}
cout << tot << "\n";
}
}
}
int main() {
int t = 1; // cin >> t;
while (t--) solve();
}
/**
* TASK: Regions (IOI)
* The idea: for regions with size > sqrt(N), precompute
* the result. Otherwise, answer the queries online...
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
344 KB |
Output is correct |
3 |
Correct |
2 ms |
504 KB |
Output is correct |
4 |
Correct |
2 ms |
344 KB |
Output is correct |
5 |
Correct |
3 ms |
344 KB |
Output is correct |
6 |
Correct |
10 ms |
344 KB |
Output is correct |
7 |
Correct |
14 ms |
344 KB |
Output is correct |
8 |
Correct |
18 ms |
600 KB |
Output is correct |
9 |
Correct |
25 ms |
856 KB |
Output is correct |
10 |
Correct |
60 ms |
1112 KB |
Output is correct |
11 |
Correct |
91 ms |
1592 KB |
Output is correct |
12 |
Correct |
93 ms |
1888 KB |
Output is correct |
13 |
Correct |
132 ms |
1912 KB |
Output is correct |
14 |
Correct |
213 ms |
2540 KB |
Output is correct |
15 |
Correct |
235 ms |
4672 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1637 ms |
6468 KB |
Output is correct |
2 |
Correct |
1977 ms |
5676 KB |
Output is correct |
3 |
Correct |
2597 ms |
8244 KB |
Output is correct |
4 |
Correct |
201 ms |
2624 KB |
Output is correct |
5 |
Correct |
281 ms |
4140 KB |
Output is correct |
6 |
Correct |
410 ms |
6160 KB |
Output is correct |
7 |
Correct |
913 ms |
7940 KB |
Output is correct |
8 |
Correct |
764 ms |
14340 KB |
Output is correct |
9 |
Correct |
1973 ms |
12840 KB |
Output is correct |
10 |
Correct |
2523 ms |
26812 KB |
Output is correct |
11 |
Correct |
4056 ms |
14292 KB |
Output is correct |
12 |
Correct |
1194 ms |
15604 KB |
Output is correct |
13 |
Correct |
1734 ms |
15512 KB |
Output is correct |
14 |
Correct |
1912 ms |
17372 KB |
Output is correct |
15 |
Correct |
2797 ms |
18920 KB |
Output is correct |
16 |
Correct |
2643 ms |
22140 KB |
Output is correct |
17 |
Correct |
2454 ms |
22900 KB |
Output is correct |