結果
問題 | No.2337 Equidistant |
ユーザー |
👑 |
提出日時 | 2023-06-02 23:28:42 |
言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 676 ms / 4,000 ms |
コード長 | 3,337 bytes |
コンパイル時間 | 1,404 ms |
コンパイル使用メモリ | 109,372 KB |
実行使用メモリ | 47,988 KB |
最終ジャッジ日時 | 2024-12-28 22:56:22 |
合計ジャッジ時間 | 13,578 ms |
ジャッジサーバーID (参考情報) |
judge1 / judge2 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 1 |
other | AC * 28 |
ソースコード
#include <cassert>#include <cmath>#include <cstdint>#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <bitset>#include <complex>#include <deque>#include <functional>#include <iostream>#include <limits>#include <map>#include <numeric>#include <queue>#include <set>#include <sstream>#include <string>#include <unordered_map>#include <unordered_set>#include <utility>#include <vector>using namespace std;using Int = long long;template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i>= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }int N;vector<int> A, B;vector<vector<int>> graph;vector<int> par, dep, sz;void dfs(int u, int p) {par[u] = p;dep[u] = ~p ? (dep[p] + 1) : 0;sz[u] = 1;for (const int v : graph[u]) if (p != v) {dfs(v, u);sz[u] += sz[v];}}// par, dep// N <= 2^Econstexpr int E = 18;int ppar[E][200'010];int lca(int u, int v) {for (int e = E; --e >= 0; ) {if (dep[u] - (1 << e) >= dep[v]) {u = ppar[e][u];}if (dep[v] - (1 << e) >= dep[u]) {v = ppar[e][v];}}for (int e = E; --e >= 0; ) {if (ppar[e][u] != ppar[e][v]) {u = ppar[e][u];v = ppar[e][v];}}if (u != v) {u = ppar[0][u];v = ppar[0][v];}return u;}int up(int u, int d) {assert(dep[u] >= d);for (int e = E; --e >= 0; ) if (d >> e & 1) u = ppar[e][u];return u;}int main() {int Q;for (; ~scanf("%d%d", &N, &Q); ) {A.resize(N - 1);B.resize(N - 1);for (int i = 0; i < N - 1; ++i) {scanf("%d%d", &A[i], &B[i]);--A[i];--B[i];}graph.assign(N, {});for (int i = 0; i < N - 1; ++i) {graph[A[i]].push_back(B[i]);graph[B[i]].push_back(A[i]);}par.assign(N, -1);dep.assign(N, -1);sz.assign(N, -1);dfs(0, -1);copy(par.begin(), par.end(), ppar[0]);for (int e = 0; e < E - 1; ++e) {for (int u = 0; u < N; ++u) {const int p = ppar[e][u];ppar[e + 1][u] = (~p) ? ppar[e][p] : -1;}}for (int q = 0; q < Q; ++q) {int S, T;scanf("%d%d", &S, &T);--S;--T;int ans = 0;const int l = lca(S, T);const int ds = dep[S] - dep[l];const int dt = dep[T] - dep[l];if ((ds + dt) % 2 == 0) {const int d = (ds + dt) / 2;if (ds > dt) {ans += sz[up(S, d)];ans -= sz[up(S, d - 1)];} else if (ds < dt) {ans += sz[up(T, d)];ans -= sz[up(T, d - 1)];} else {ans += N;ans -= sz[up(S, d - 1)];ans -= sz[up(T, d - 1)];}}printf("%d\n", ans);}}return 0;}