#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = long double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
#define mp make_pair
#define f first
#define s second
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
#define lb lower_bound
#define ub upper_bound
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
const int MOD = 1e9 + 7;
const int MXN = 2e5 + 10;
const int MXR = 25010;
const ll INF = 1e18;
const int BLOCK = 450;
int N, R, Q; vi adj[MXN]; int L[MXN]; // L[i] = Region of i
int timer = 1, in[MXN], out[MXN]; vi S[MXR]; // Sorted list of {in, out} for each region
vi large; int up[BLOCK][MXR], down[BLOCK][MXR];
int ind[MXN];
// Preorder Traversal ~ O(N)
void DFS(int X, int P) {
in[X] = timer++; S[L[X]].pb(X);
EACH(Y, adj[X]) if (Y != P) DFS(Y, X); out[X] = timer - 1;
}
bool isAnc(int A, int B) { return in[A] <= in[B] && out[B] <= out[A]; }
// Get the answer when queried (A, B) ~ O(N)
int genAns(int A, int B) {
int ans = 0; int L = 0, R = 0; int last = 0; deque<int> anc;
while (L < sz(S[A]) || R < sz(S[B])) {
if (L < sz(S[A]) && (R >= sz(S[B]) || in[S[A][L]] < in[S[B][R]])) {
while (sz(anc) && !isAnc(anc.bk, S[A][L])) anc.pop_back(); anc.pb(S[A][L++]);
}
else { while (sz(anc) && !isAnc(anc.bk, S[B][R])) anc.pop_back(); ans += sz(anc); R++; }
}
return ans;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> N >> R >> Q >> L[1];
FOR(i, 2, N + 1) { int A; cin >> A >> L[i]; adj[A].pb(i), adj[i].pb(A); }
DFS(1, 0);
int cur = 0; FOR(i, 1, R + 1) if (sz(S[i]) >= BLOCK) large.pb(i), ind[i] = cur++;
F0R(i, sz(large)) {
FOR(j, 1, R + 1) {
up[i][j] = genAns(large[i], j);
down[i][j] = genAns(j, large[i]);
}
}
F0R(i, Q) {
int A, B; cin >> A>> B;
if (sz(S[A]) >= BLOCK) cout << up[ind[A]][B] << endl;
else if (sz(S[B]) >= BLOCK) cout << down[ind[B]][A] << endl;
else cout << genAns(A, B) << endl;
}
}
Compilation message
regions.cpp: In function 'void DFS(int, int)':
regions.cpp:42:20: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
42 | #define EACH(a, x) for (auto& a : x)
| ^~~
regions.cpp:64:5: note: in expansion of macro 'EACH'
64 | EACH(Y, adj[X]) if (Y != P) DFS(Y, X); out[X] = timer - 1;
| ^~~~
regions.cpp:64:44: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
64 | EACH(Y, adj[X]) if (Y != P) DFS(Y, X); out[X] = timer - 1;
| ^~~
regions.cpp: In function 'int genAns(int, int)':
regions.cpp:75:13: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
75 | while (sz(anc) && !isAnc(anc.bk, S[A][L])) anc.pop_back(); anc.pb(S[A][L++]);
| ^~~~~
regions.cpp:75:72: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
75 | while (sz(anc) && !isAnc(anc.bk, S[A][L])) anc.pop_back(); anc.pb(S[A][L++]);
| ^~~
regions.cpp:71:40: warning: unused variable 'last' [-Wunused-variable]
71 | int ans = 0; int L = 0, R = 0; int last = 0; deque<int> anc;
| ^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
5576 KB |
Output is correct |
| 2 |
Correct |
5 ms |
5576 KB |
Output is correct |
| 3 |
Correct |
5 ms |
5576 KB |
Output is correct |
| 4 |
Correct |
9 ms |
5576 KB |
Output is correct |
| 5 |
Correct |
12 ms |
5576 KB |
Output is correct |
| 6 |
Correct |
23 ms |
5576 KB |
Output is correct |
| 7 |
Correct |
43 ms |
5576 KB |
Output is correct |
| 8 |
Correct |
46 ms |
5704 KB |
Output is correct |
| 9 |
Correct |
63 ms |
6088 KB |
Output is correct |
| 10 |
Correct |
54 ms |
6088 KB |
Output is correct |
| 11 |
Correct |
110 ms |
6344 KB |
Output is correct |
| 12 |
Correct |
92 ms |
6740 KB |
Output is correct |
| 13 |
Correct |
209 ms |
6776 KB |
Output is correct |
| 14 |
Correct |
284 ms |
7036 KB |
Output is correct |
| 15 |
Correct |
379 ms |
9416 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1497 ms |
10132 KB |
Output is correct |
| 2 |
Correct |
1569 ms |
9848 KB |
Output is correct |
| 3 |
Correct |
2506 ms |
11720 KB |
Output is correct |
| 4 |
Correct |
324 ms |
7244 KB |
Output is correct |
| 5 |
Correct |
499 ms |
8520 KB |
Output is correct |
| 6 |
Correct |
5760 ms |
12432 KB |
Output is correct |
| 7 |
Correct |
3006 ms |
10752 KB |
Output is correct |
| 8 |
Execution timed out |
8029 ms |
20032 KB |
Time limit exceeded |
| 9 |
Correct |
2661 ms |
14212 KB |
Output is correct |
| 10 |
Execution timed out |
8055 ms |
24568 KB |
Time limit exceeded |
| 11 |
Correct |
3632 ms |
16292 KB |
Output is correct |
| 12 |
Execution timed out |
8031 ms |
15424 KB |
Time limit exceeded |
| 13 |
Execution timed out |
8009 ms |
16316 KB |
Time limit exceeded |
| 14 |
Execution timed out |
8025 ms |
16836 KB |
Time limit exceeded |
| 15 |
Execution timed out |
8048 ms |
19436 KB |
Time limit exceeded |
| 16 |
Execution timed out |
8050 ms |
25172 KB |
Time limit exceeded |
| 17 |
Execution timed out |
8010 ms |
24704 KB |
Time limit exceeded |
