結果

問題 No.1326 ふたりのDominator
ユーザー suisen
提出日時 2022-12-12 01:04:46
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 175 ms / 2,000 ms
コード長 10,027 bytes
コンパイル時間 2,640 ms
コンパイル使用メモリ 216,844 KB
最終ジャッジ日時 2025-02-09 09:51:38
ジャッジサーバーID
（参考情報） 		judge5 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 24
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ソースコード

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プレゼンテーションモードにする

#line 1 "test/graph/bcc/yuki1326.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/1326"
#line 2 "src/Template.hpp"
#define CUT
#include <bits/stdc++.h>
using namespace std;
#define rep(i, l, r) for (int i = (l); i < (r); ++i)
#define rrep(i, l, r) for (int i = (r); i --> (l);)
#define all(c) begin(c), end(c)
#ifdef LOCAL
#define debug(...) debug_impl(#__VA_ARGS__, __VA_ARGS__)
template <class H, class... Ts> void debug_impl(string s, H&& h, Ts&&... ts) {
  cerr << '(' << s << "): (" << forward<H>(h);
  ((cerr << ", " << forward<Ts>(ts)), ..., (cerr << ")\n"));
}
#else
#define debug(...) void(0)
#endif
template <class T> bool chmax(T& a, const T& b) { return b > a ? (a = b, true) : false; }
template <class T> bool chmin(T& a, const T& b) { return b < a ? (a = b, true) : false; }
template <class T> istream& operator>>(istream& in, vector<T>& v) {
  for (auto& e : v) in >> e;
  return in;
}
template <class ...Args> void read(Args&... args) {
  (cin >> ... >> args);
}
template <class T> ostream& operator<<(ostream& out, const vector<T>& v) {
  int n = v.size();
  rep(i, 0, n) {
    out << v[i];
    if (i + 1 != n) out << ' ';
  }
  return out;
}
template <class H, class ...Ts> void print(H&& h, Ts &&... ts) {
  cout << h, ((cout << ' ' << forward<Ts>(ts)), ..., (cout << '\n'));
}
struct io_setup_ {
  io_setup_() {
    ios::sync_with_stdio(false), cin.tie(nullptr);
    cout << fixed << setprecision(10);
  }
} io_setup{};
#undef CUT
#define NOTE compile command: \texttt{g++ -std=gnu++17 -Wall -Wextra -g -fsanitize=address -fsanitize=undefined \$\{file\} -o \$\{fileDirname\}
    /\$\{fileBasenameNoExtension\}}
#undef NOTE
#define NOTE \texttt{-DLOCAL} を加えると \texttt{debug(...)} による出力が有効となる
#undef NOTE
#line 3 "src/tree/HLD.hpp"
#define CUT
struct HLD {
  int n;
  vector<int> visit, leave, head, ord, siz, par, dep;
private:
  int dfs(vector<vector<int>>& g, int u, int p) {
    par[u] = p;
    int maxsiz = 0;
    for (int& v : g[u]) if (v != p) {
      dep[v] = dep[u] + 1;
      siz[u] += dfs(g, v, u);
      if (chmax(maxsiz, siz[v])) swap(g[u][0], v);
    }
    return siz[u];
  }
  int time = 0;
  void hld(const vector<vector<int>>& g, int u, int p) {
    visit[u] = time, ord[time] = u, ++time;
    head[u] = p >= 0 and g[p][0] == u ? head[p] : u;
    for (int v : g[u]) if (v != p) hld(g, v, u);
    leave[u] = time;
  }
public:
  HLD() = default;
  HLD(vector<vector<int>>& g, vector<int> roots = {}):
    n(g.size()), visit(n), leave(n), head(n), ord(n), siz(n, 1), par(n, -1), dep(n) {
    for (int r : roots) if (par[r] < 0) dfs(g, r, -1);
    rep(r, 0, n) if (par[r] < 0) dfs(g, r, -1);
    rep(r, 0, n) if (par[r] < 0) hld(g, r, -1);
  }
  int size() const { return n; }
  int lca(int u, int v) const {
    for (;; v = par[head[v]]) {
      if (visit[u] > visit[v]) swap(u, v);
      if (head[u] == head[v]) return u;
    }
  }
  int la(int u, int k) const {
    if (k < 0) return -1;
    while (u >= 0) {
      int h = head[u];
      if (visit[u] - k >= visit[h]) return ord[visit[u] - k];
      k -= visit[u] - visit[h] + 1;
      u = par[h];
    }
    return -1;
  }
  int jump(int u, int v, int d) const {
    if (d < 0) return -1;
    int w = lca(u, v);
    int uw = dep[u] - dep[w];
    if (d <= uw) return la(u, d);
    int vw = dep[v] - dep[w];
    return d <= uw + vw ? la(v, (uw + vw) - d) : -1;
  }
  int dist(int u, int v) const {
    return dep[u] + dep[v] - 2 * dep[lca(u, v)];
  }
  vector<pair<int, int>> get_path(int u, int v, bool is_edge_query) const {
    vector<pair<int, int>> res;
    for (;; v = par[head[v]]) {
      if (visit[u] > visit[v]) swap(u, v);
      if (head[u] == head[v]) break;
      res.emplace_back(visit[head[v]], visit[v] + 1);
    }
    res.emplace_back(visit[u] + is_edge_query, visit[v] + 1);
    return res;
  }
  // uvパス上の値を順番通りに掛けた結果を返す
  template <class T, class Op, class Prod, class RevProd>
  T fold_path_ordered(int u, int v, Op op, T e, Prod prod, RevProd rev_prod, bool is_edge_query) const {
    int w = lca(u, v);
    T sml = e, smr = e;
    for (auto [l, r] : get_path(u, w, is_edge_query)) sml = op(sml, rev_prod(l, r));
    for (auto [l, r] : get_path(v, w, true)) smr = op(prod(l, r), smr);
    return op(sml, smr);
  }
  pair<int, int> get_subtree(int u, bool is_edge_query) const {
    return { visit[u] + is_edge_query, leave[u] };
  }
  // vertex->id
  int get_id(int u) const {
    return visit[u];
  }
  // id->vertexのvector
  vector<int> inv_ids() const {
    vector<int> inv(n);
    rep(i, 0, n) inv[visit[i]] = i;
    return inv;
  }
  vector<int> roots() const {
    vector<int> res;
    rep(i, 0, n) if (par[i] < 0) res.push_back(i);
    return res;
  }
};
#undef CUT
#line 3 "src/graph/BCC.hpp"
#define CUT
#line 2 "src/graph/LowLink.hpp"
#line 4 "src/graph/LowLink.hpp"
#define CUT
struct LowLink {
  int n, m;
  vector<pair<int, int>> edges;
  vector<vector<pair<int, int>>> g;
  vector<int> ord, low, a_ids, b_ids;
  bool built = false;
  LowLink(const int n = 0): n(n), m(0), g(n), ord(n, -1), low(n) {}
  // Returns the id of the added edge
  int add_edge(int u, int v) {
    built = false;
    edges.emplace_back(u, v);
    g[u].emplace_back(v, m);
    g[v].emplace_back(u, m);
    return m++;
  }
  void build() {
    if (exchange(built, true)) return;
    int t = 0;
    auto dfs = [&](auto dfs, int u, int id) -> void {
      bool is_root = id < 0, is_art = false;
      int cnt = 0;
      ord[u] = low[u] = t++;
      for (auto [v, id2] : g[u]) if (id != id2) {
        if (ord[v] < 0) {
          ++cnt;
          dfs(dfs, v, id2);
          chmin(low[u], low[v]);
          if (ord[u] <= low[v]) {
            is_art = not is_root;
            if (ord[u] != low[v]) b_ids.push_back(id2);
          }
        } else {
          chmin(low[u], ord[v]);
        }
      }
      if (is_art or (is_root and cnt > 1)) {
        a_ids.push_back(u);
      }
    };
    rep(i, 0, n) if (ord[i] < 0) dfs(dfs, i, -1);
  }
  // Returns `\{i \mid \text{$e_i$ is a bridge} \}`
  const vector<int>& bridge_ids() {
    return build(), b_ids;
  }
  // Returns `\{i \mid \text{$v_i$ is an articulation point} \}`
  const vector<int>& articulation_points() {
    return build(), a_ids;
  }
  bool is_bridge(int u, int v) {
    build();
    if (ord[u] > ord[v]) swap(u, v);
    return ord[u] < low[v];
  }
};
#undef CUT
#line 5 "src/graph/BCC.hpp"
struct BCC {
  // isolated vertex <-> eid is empty
  vector<int> vids, eids;
};
struct BCCDecomp: LowLink {
  // cid[i]: the id of BCC to which `e_i` belongs
  vector<int> cid;
  // isolated vertices
  vector<int> iso;
  BCCDecomp(int n = 0): LowLink(n) {}
  int build() {
    if (built) return iso.size() + (m ? *max_element(all(cid)) + 1 : 0);
    LowLink::build();
    vector<int8_t> used(n);
    int num = 0;
    cid.assign(m, -1);
    auto dfs = [&](auto dfs, int u, int peid) -> void {
      used[u] = true;
      static vector<int> edges;
      for (const auto& [v, eid] : g[u]) if (eid != peid) {
        if (not used[v] or ord[v] < ord[u]) edges.push_back(eid);
        if (used[v]) continue;
        dfs(dfs, v, eid);
        if (low[v] < ord[u]) continue;
        int e;
        do cid[e = edges.back()] = num, edges.pop_back(); while (e != eid);
        num++;
      }
    };
    for (int i = 0; i < n; ++i) if (not used[i]) {
      dfs(dfs, i, -1);
      if (g[i].empty()) iso.push_back(i);
    }
    return num + iso.size();
  }
  vector<BCC> bcc() {
    const int num = build(), vcmp = iso.size(), ecmp = num - vcmp;
    vector<BCC> res(num);
    rep(i, 0, m) {
      res[cid[i]].eids.push_back(i);
    }
    vector<int8_t> seen(n, false);
    rep(id, 0, ecmp) {
      for (int eid : res[id].eids) {
        const auto& [u, v] = edges[eid];
        if (not exchange(seen[u], true)) res[id].vids.push_back(u);
        if (not exchange(seen[v], true)) res[id].vids.push_back(v);
      }
      for (int v : res[id].vids) seen[v] = false;
    }
    rep(id, 0, vcmp) {
      res[ecmp + id].vids = { iso[id] };
    }
    return res;
  }
  // Let `C := \text{set of BCC}` and `A := \text{set of articulation points}`
  // Vertex set of BCT `V := C\sqcup A` (`0 \leq i < |C|` corresponds to the `i`-th BCC and `|C| \leq i < |C| + |A|` corresponds to the `(i-|C|)`-th 
      articulation point)
  // Edge set of BCT `E := \{(c, a) \in C\times A \mid a \in V(C) \}`
  vector<vector<int>> block_cut_tree(const vector<BCC> &bccs) {
    const int cnum = bccs.size(), anum = a_ids.size();
    vector<int> ids(n, -1);
    rep(i, 0, anum) {
      ids[a_ids[i]] = cnum + i;
    }
    vector<vector<int>> res(cnum + anum);
    rep(i, 0, cnum) {
      for (int v : bccs[i].vids) {
        if (int j = ids[v]; j >= 0) {
          res[i].push_back(j);
          res[j].push_back(i);
        }
      }
    }
    return res;
  }
  // Let `C := \text{set of BCC}` and `A := \text{the vertex set of original graph}`
  // Vertex set of BCT `V := C\sqcup A` (`0 \leq i < |C|` corresponds to the `i`-th BCC and `|C| \leq i < |C| + |A|` corresponds to the `(i-|C|)`-th 
      vertex)
  // Edge set of BCT `E := \{(c, a) \in C\times A \mid a \in V(C) \}`
  vector<vector<int>> ext_block_cut_tree(const vector<BCC> &bccs) {
    const int cnum = bccs.size();
    vector<vector<int>> res(cnum + n);
    rep(i, 0, cnum) {
      for (int v : bccs[i].vids) {
        res[i].push_back(cnum + v);
        res[cnum + v].push_back(i);
      }
    }
    return res;
  }
};
#undef CUT
#define NOTE 多重辺・自己ループがあってもよい
#undef NOTE
#line 5 "test/graph/bcc/yuki1326.test.cpp"
int main() {
  int n, m;
  read(n, m);
  BCCDecomp bccd(n);
  rep(i, 0, m) {
    int u, v;
    read(u, v);
    --u, --v;
    bccd.add_edge(u, v);
  }
  auto bcc = bccd.bcc();
  auto bct = bccd.ext_block_cut_tree(bcc);
  HLD hld(bct);
  const int k = bcc.size();
  int q;
  read(q);
  rep(qid, 0, q) {
    int x, y;
    read(x, y);
    --x, --y;
    print(max(0, hld.dist(k + x, k + y) / 2 - 1));
  }
}
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