結果
問題 | No.2337 Equidistant |
ユーザー | 👑 emthrm |
提出日時 | 2023-06-02 21:40:57 |
言語 | C++23 (gcc 12.3.0 + boost 1.83.0) |
結果 |
AC
|
実行時間 | 1,125 ms / 4,000 ms |
コード長 | 3,880 bytes |
コンパイル時間 | 3,455 ms |
コンパイル使用メモリ | 263,812 KB |
実行使用メモリ | 49,560 KB |
最終ジャッジ日時 | 2024-06-08 22:33:40 |
合計ジャッジ時間 | 14,838 ms |
ジャッジサーバーID (参考情報) |
judge1 / judge4 |
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テストケース
テストケース表示入力 | 結果 | 実行時間 実行使用メモリ |
---|---|---|
testcase_00 | AC | 2 ms
5,248 KB |
testcase_01 | AC | 2 ms
5,248 KB |
testcase_02 | AC | 2 ms
5,376 KB |
testcase_03 | AC | 2 ms
5,376 KB |
testcase_04 | AC | 2 ms
5,376 KB |
testcase_05 | AC | 2 ms
5,376 KB |
testcase_06 | AC | 4 ms
5,376 KB |
testcase_07 | AC | 4 ms
5,376 KB |
testcase_08 | AC | 4 ms
5,376 KB |
testcase_09 | AC | 4 ms
5,376 KB |
testcase_10 | AC | 3 ms
5,376 KB |
testcase_11 | AC | 414 ms
41,856 KB |
testcase_12 | AC | 419 ms
41,856 KB |
testcase_13 | AC | 438 ms
41,728 KB |
testcase_14 | AC | 437 ms
41,856 KB |
testcase_15 | AC | 421 ms
41,728 KB |
testcase_16 | AC | 408 ms
41,728 KB |
testcase_17 | AC | 405 ms
41,728 KB |
testcase_18 | AC | 405 ms
41,728 KB |
testcase_19 | AC | 402 ms
41,856 KB |
testcase_20 | AC | 425 ms
41,728 KB |
testcase_21 | AC | 634 ms
49,560 KB |
testcase_22 | AC | 348 ms
43,196 KB |
testcase_23 | AC | 335 ms
42,880 KB |
testcase_24 | AC | 828 ms
46,616 KB |
testcase_25 | AC | 376 ms
43,008 KB |
testcase_26 | AC | 1,125 ms
46,484 KB |
testcase_27 | AC | 409 ms
42,880 KB |
testcase_28 | AC | 400 ms
42,880 KB |
ソースコード
#include <bits/stdc++.h> using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) (v).begin(),(v).end() using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 998244353; // constexpr int MOD = 1000000007; constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1}; constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}; constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1}; template <typename T, typename U> inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; } template <typename T, typename U> inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; struct LowestCommonAncestorByDoubling { std::vector<int> depth; vector<int> sub; explicit LowestCommonAncestorByDoubling( const std::vector<std::vector<int>>& graph) : is_built(false), n(graph.size()), table_h(std::countr_zero(std::bit_floor(graph.size())) + 1), graph(graph) { depth.resize(n); sub.resize(n, 1); parent.resize(table_h, std::vector<int>(n)); } void build(int root = 0) { is_built = true; dfs(-1, root, 0); for (int i = 0; i + 1 < table_h; ++i) { for (int ver = 0; ver < n; ++ver) { parent[i + 1][ver] = (parent[i][ver] == -1 ? -1 : parent[i][parent[i][ver]]); } } } int query(int u, int v) const { assert(is_built); if (depth[u] > depth[v]) std::swap(u, v); for (int i = 0; i < table_h; ++i) { if ((depth[v] - depth[u]) >> i & 1) v = parent[i][v]; } if (u == v) return u; for (int i = table_h - 1; i >= 0; --i) { if (parent[i][u] != parent[i][v]) { u = parent[i][u]; v = parent[i][v]; } } return parent.front()[u]; } int distance(const int u, const int v) const { assert(is_built); return depth[u] + depth[v] - depth[query(u, v)] * 2; } int level_ancestor(int v, const int d) const { assert(is_built); if (depth[v] < d) return -1; for (int i = depth[v] - d, bit = 0; i > 0; i >>= 1, ++bit) { if (i & 1) v = parent[bit][v]; } return v; } int jump(const int u, const int v, const int d) const { assert(is_built); if (d == 0) [[unlikely]] return u; const int l = query(u, v), d_lu = depth[u] - depth[l]; if (d_lu == d) return l; if (d_lu > d) return level_ancestor(u, depth[u] - d); return level_ancestor(v, depth[l] + (d - d_lu)); } private: bool is_built; const int n, table_h; const std::vector<std::vector<int>> graph; std::vector<std::vector<int>> parent; void dfs(const int par, const int ver, const int cur_depth) { depth[ver] = cur_depth; parent.front()[ver] = par; for (const int e : graph[ver]) { if (e != par) { dfs(ver, e, cur_depth + 1); sub[ver] += sub[e]; } } } }; int main() { int n, q; cin >> n >> q; vector<vector<int>> graph(n); REP(_, n - 1) { int a, b; cin >> a >> b; --a; --b; graph[a].emplace_back(b); graph[b].emplace_back(a); } LowestCommonAncestorByDoubling lca(graph); lca.build(); while (q--) { int s, t; cin >> s >> t; --s; --t; const int d = lca.distance(s, t); if (d % 2 == 1) { cout << 0 << '\n'; } else { const int root = lca.jump(s, t, d / 2); const int ad_s = lca.jump(root, s, 1), ad_t = lca.jump(root, t, 1); if (lca.depth[ad_s] == lca.depth[ad_t]) { cout << n - lca.sub[ad_s] - lca.sub[ad_t] << '\n'; } else { const int ch = (lca.depth[ad_s] > lca.depth[ad_t] ? ad_s : ad_t); cout << lca.sub[root] - lca.sub[ch] << '\n'; } } } return 0; }