#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> r, g;
vector<int> euler, in, out, fr;
vector<short int> c;
int t;
const short int block = 447;
void dfs(int u) {
in[u] = t++;
euler.push_back(u);
for (int v : g[u])
dfs(v);
out[u] = t - 1;
}
void add(int x) {
fr[c[euler[x]]]++;
}
void remove(int x) {
fr[c[euler[x]]]--;
}
int main() {
int n, rr, qq;
cin >> n >> rr >> qq;
g.resize(n), r.resize(rr), in.resize(n), out.resize(n), fr.resize(rr), c.resize(n), q.resize(qq);
vector<unordered_map<short int, int>> ans(rr);
int x, h;
cin >> h;
h--;
r[h].push_back(0);
c[0] = h;
for (int i = 1; i < n; i++) {
cin >> x >> h;
x--, h--;
r[h].push_back(i);
g[x].push_back(i);
c[i] = h;
}
dfs(0);
for (int i = 0; i < rr; i++) {
sort(r[i].begin(), r[i].end(), [](const int &a, const int &b) {
int a1 = in[a] / block, b1 = in[b] / block;
return a1 == b1 ? out[a] < out[b] : a1 < b1;
});
}
for (int i = 0; i < rr; i++) {
int lb, rb;
if (r[i].size()) lb = in[r[i][0]] + 1, rb = lb - 1;
for (int u : r[i]) {
int l_ = in[u] + 1, r_ = out[u];
while (lb > l_) add(--lb);
while (rb < r_) add(++rb);
while (lb < l_) remove(lb++);
while (rb > r_) remove(rb--);
for (int j = 0; j < rr; j++)
if (fr[j]) ans[i][j] += fr[j];
}
if (r[i].size()) for (int j = 0; j < rr; j++) fr[j] = 0;
}
while (qq--) {
int a, b;
cin >> a >> b;
cout << ans[--a][--b] << endl;
}
}
Compilation message
regions.cpp: In function 'int main()':
regions.cpp:29:89: error: 'q' was not declared in this scope; did you mean 'qq'?
29 | g.resize(n), r.resize(rr), in.resize(n), out.resize(n), fr.resize(rr), c.resize(n), q.resize(qq);
| ^
| qq
