結果
問題 | No.2337 Equidistant |
ユーザー |
|
提出日時 | 2023-06-02 21:49:08 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 264 ms / 4,000 ms |
コード長 | 9,638 bytes |
コンパイル時間 | 2,457 ms |
コンパイル使用メモリ | 207,948 KB |
最終ジャッジ日時 | 2025-02-13 18:02:37 |
ジャッジサーバーID (参考情報) |
judge3 / 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 <bits/stdc++.h>using namespace std;#define rep(i, n) for (int i = 0; i < (n); i++)#define per(i, n) for (int i = (n)-1; i >= 0; i--)#define rep2(i, l, r) for (int i = (l); i < (r); i++)#define per2(i, l, r) for (int i = (r)-1; i >= (l); i--)#define each(e, v) for (auto &e : v)#define MM << " " <<#define pb push_back#define eb emplace_back#define all(x) begin(x), end(x)#define rall(x) rbegin(x), rend(x)#define sz(x) (int)x.size()using ll = long long;using pii = pair<int, int>;using pil = pair<int, ll>;using pli = pair<ll, int>;using pll = pair<ll, ll>;template <typename T>using minheap = priority_queue<T, vector<T>, greater<T>>;template <typename T>using maxheap = priority_queue<T>;template <typename T>bool chmax(T &x, const T &y) {return (x < y) ? (x = y, true) : false;}template <typename T>bool chmin(T &x, const T &y) {return (x > y) ? (x = y, true) : false;}template <typename T>int flg(T x, int i) {return (x >> i) & 1;}int pct(int x) { return __builtin_popcount(x); }int pct(ll x) { return __builtin_popcountll(x); }int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }int topbit(ll x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }int botbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }int botbit(ll x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }template <typename T>void print(const vector<T> &v, T x = 0) {int n = v.size();for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' ');if (v.empty()) cout << '\n';}template <typename T>void printn(const vector<T> &v, T x = 0) {int n = v.size();for (int i = 0; i < n; i++) cout << v[i] + x << '\n';}template <typename T>int lb(const vector<T> &v, T x) {return lower_bound(begin(v), end(v), x) - begin(v);}template <typename T>int ub(const vector<T> &v, T x) {return upper_bound(begin(v), end(v), x) - begin(v);}template <typename T>void rearrange(vector<T> &v) {sort(begin(v), end(v));v.erase(unique(begin(v), end(v)), end(v));}template <typename T>vector<int> id_sort(const vector<T> &v, bool greater = false) {int n = v.size();vector<int> ret(n);iota(begin(ret), end(ret), 0);sort(begin(ret), end(ret), [&](int i, int j) { return greater ? v[i] > v[j] : v[i] < v[j]; });return ret;}template <typename T>void reorder(vector<T> &a, const vector<int> &ord) {int n = a.size();vector<T> b(n);for (int i = 0; i < n; i++) b[i] = a[ord[i]];swap(a, b);}template <typename T>T floor(T x, T y) {assert(y != 0);if (y < 0) x = -x, y = -y;return (x >= 0 ? x / y : (x - y + 1) / y);}template <typename T>T ceil(T x, T y) {assert(y != 0);if (y < 0) x = -x, y = -y;return (x >= 0 ? (x + y - 1) / y : x / y);}template <typename S, typename T>pair<S, T> operator+(const pair<S, T> &p, const pair<S, T> &q) {return make_pair(p.first + q.first, p.second + q.second);}template <typename S, typename T>pair<S, T> operator-(const pair<S, T> &p, const pair<S, T> &q) {return make_pair(p.first - q.first, p.second - q.second);}template <typename S, typename T>istream &operator>>(istream &is, pair<S, T> &p) {S a;T b;is >> a >> b;p = make_pair(a, b);return is;}template <typename S, typename T>ostream &operator<<(ostream &os, const pair<S, T> &p) {return os << p.first << ' ' << p.second;}struct io_setup {io_setup() {ios_base::sync_with_stdio(false);cin.tie(NULL);cout << fixed << setprecision(15);}} io_setup;constexpr int inf = (1 << 30) - 1;constexpr ll INF = (1LL << 60) - 1;// constexpr int MOD = 1000000007;constexpr int MOD = 998244353;template <bool directed = false>struct Heavy_Light_Decomposition {struct edge {int to, id;edge(int to, int id) : to(to), id(id) {}};vector<vector<edge>> es;vector<int> par, si, depth;vector<int> root; // 属する連結成分の根vector<int> id_v, id_e; // 各頂点、各辺が一列に並べたときに何番目に相当するか (辺の番号は 1,2,...,n-1 となることに注意)vector<int> vs;const int n;int m;Heavy_Light_Decomposition(int n) : es(n), par(n), si(n, 1), depth(n, -1), root(n), id_v(n), id_e(n - 1), vs(n), n(n), m(0) {}void add_edge(int from, int to) {es[from].emplace_back(to, m);if (!directed) es[to].emplace_back(from, m);m++;}int bfs_sz(int r, int s) {int t = s;queue<int> que;que.push(r);depth[r] = 0;vs[t++] = r;while (!que.empty()) {int i = que.front();que.pop();for (auto &e : es[i]) {if (depth[e.to] != -1) continue;par[e.to] = i;depth[e.to] = depth[i] + 1;vs[t++] = e.to;que.push(e.to);}}for (int i = t - 1; i >= s; i--) {for (auto &e : es[vs[i]]) {if (e.to != par[vs[i]]) si[vs[i]] += si[e.to];}}return t;}void bfs_hld(int r, int s) {id_v[r] = s;root[r] = r;queue<int> que;que.push(r);while (!que.empty()) {int i = que.front();que.pop();edge heavy = {-1, -1};int ma = 0;for (auto &e : es[i]) {if (e.to == par[i]) continue;if (ma < si[e.to]) ma = si[e.to], heavy = e;}int cnt = id_v[i] + 1;if (heavy.id != -1) {root[heavy.to] = root[i];id_e[heavy.id] = cnt;id_v[heavy.to] = cnt;que.push(heavy.to);cnt += si[heavy.to];}for (auto &e : es[i]) {if (e.to == par[i] || e.id == heavy.id) continue;root[e.to] = e.to;id_e[e.id] = cnt;id_v[e.to] = cnt;que.push(e.to);cnt += si[e.to];}}}void decompose() {int s = 0;for (int i = 0; i < n; i++) {if (depth[i] != -1) continue;int t = bfs_sz(i, s);bfs_hld(i, s);s = t;}for (int i = 0; i < n; i++) vs[id_v[i]] = i;}int lca(int u, int v) {while (root[u] != root[v]) {if (depth[root[u]] > depth[root[v]]) swap(u, v);v = par[root[v]];}if (depth[u] > depth[v]) swap(u, v);return u;}int dist(int u, int v) { return depth[u] + depth[v] - depth[lca(u, v)] * 2; }// u の k 個前の祖先int ancestor(int u, int k) {if (k > depth[u]) return -1;while (k > 0) {int r = root[u];int l = depth[u] - depth[r];if (k <= l) return vs[id_v[r] + l - k];u = par[r];k -= l + 1;}return u;}// u から v の方向へ k 回移動int move(int u, int v, int k) {int w = lca(u, v);int l = depth[u] + depth[v] - depth[w] * 2;if (k > l) return -1;if (k <= depth[u] - depth[w]) return ancestor(u, k);return ancestor(v, l - k);}// パスに対応する区間たちを列挙vector<pair<int, int>> get_path(int u, int v, bool use_edge = false) {vector<pair<int, int>> ret;while (root[u] != root[v]) {if (depth[root[u]] > depth[root[v]]) swap(u, v);ret.emplace_back(id_v[root[v]], id_v[v] + 1);v = par[root[v]];}if (depth[u] > depth[v]) swap(u, v);ret.emplace_back(id_v[u] + use_edge, id_v[v] + 1);return ret;}// クエリが非可換の場合 (l > r なら子から親方向で [r,l)、l < r なら親から子方向で [l,r))vector<pair<int, int>> get_path_noncommutative(int u, int v, bool use_edge = false) {vector<pair<int, int>> l, r;while (root[u] != root[v]) {if (depth[root[u]] > depth[root[v]]) {l.emplace_back(id_v[u] + 1, id_v[root[u]]);u = par[root[u]];} else {r.emplace_back(id_v[root[v]], id_v[v] + 1);v = par[root[v]];}}if (depth[u] > depth[v]) {l.emplace_back(id_v[u] + 1, id_v[v] + use_edge);} else {r.emplace_back(id_v[u] + use_edge, id_v[v] + 1);}reverse(begin(r), end(r));for (auto &e : r) l.push_back(e);return l;}};void solve() {int N, Q;cin >> N >> Q;Heavy_Light_Decomposition G(N);rep(i, N - 1) {int u, v;cin >> u >> v;u--, v--;G.add_edge(u, v);}G.decompose();while (Q--) {int u, v;cin >> u >> v;u--, v--;int d = G.dist(u, v);if (d % 2 == 1) {cout << "0\n";continue;}d /= 2;if (G.depth[u] < G.depth[v]) swap(u, v);if (G.depth[u] > G.depth[v]) {int w1 = G.ancestor(u, d), w2 = G.ancestor(u, d - 1);cout << G.si[w1] - G.si[w2] << '\n';} else {int w1 = G.ancestor(u, d), w2 = G.ancestor(u, d - 1), w3 = G.ancestor(v, d - 1);cout << N - G.si[w2] - G.si[w3] << '\n';}}}int main() {int T = 1;// cin >> T;while (T--) solve();}