test/verify/yosupo-lca.test.cpp

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• Last update: 2024-05-01 23:44:47+09:00
• Problem: https://judge.yosupo.jp/problem/lca

Depends on

• Graph Template(グラフテンプレート) (graph/graph-template.hpp)
• PMORMQ-Lowest-Common-Ancestor(最小共通祖先) (graph/tree/pmormq-lowest-common-ancestor.hpp)
• Printer(高速出力) (other/printer.hpp)
• Scanner(高速入力) (other/scanner.hpp)
• Plus-Minus-One-RMQ (structure/others/plus-minus-one-rmq.hpp)
• Sparse-Table(スパーステーブル) (structure/others/sparse-table.hpp)
• template/template.hpp

Code

// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/lca

#include "../../template/template.hpp"

#include "../../graph/graph-template.hpp"
#include "../../graph/tree/pmormq-lowest-common-ancestor.hpp"

#include "../../other/scanner.hpp"
#include "../../other/printer.hpp"


int main() {
  Scanner in(stdin);
  Printer out(stdout);
  int N, Q;
  in.read(N, Q);
  PMORMQLowestCommonAncestor< int > g(N);
  for(int i = 1; i < N; i++) {
    int x;
    in.read(x);
    g.add_directed_edge(x, i);
  }
  g.build();
  for(int i = 0; i < Q; i++) {
    int u, v;
    in.read(u, v);
    out.writeln(g.lca(u, v));
  }
}

#line 1 "test/verify/yosupo-lca.test.cpp"
// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/lca

#line 1 "template/template.hpp"
#include <bits/stdc++.h>

using namespace std;

using int64 = long long;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v) is >> in;
  return is;
}

template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}

template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

template <typename T = int64>
vector<T> make_v(size_t a) {
  return vector<T>(a);
}

template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) {
  t = v;
}

template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) {
  for (auto &e : t) fill_v(e, v);
}

template <typename F>
struct FixPoint : F {
  explicit FixPoint(F &&f) : F(forward<F>(f)) {}

  template <typename... Args>
  decltype(auto) operator()(Args &&...args) const {
    return F::operator()(*this, forward<Args>(args)...);
  }
};

template <typename F>
inline decltype(auto) MFP(F &&f) {
  return FixPoint<F>{forward<F>(f)};
}
#line 4 "test/verify/yosupo-lca.test.cpp"

#line 2 "graph/graph-template.hpp"

/**
 * @brief Graph Template(グラフテンプレート)
 */
template <typename T = int>
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1)
      : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template <typename T = int>
struct Graph {
  vector<vector<Edge<T> > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  size_t size() const { return g.size(); }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false,
            bool directed = false) {
    for (int i = 0; i < M; i++) {
      int a, b;
      cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if (weighted) cin >> c;
      if (directed)
        add_directed_edge(a, b, c);
      else
        add_edge(a, b, c);
    }
  }

  inline vector<Edge<T> > &operator[](const int &k) { return g[k]; }

  inline const vector<Edge<T> > &operator[](const int &k) const { return g[k]; }
};

template <typename T = int>
using Edges = vector<Edge<T> >;
#line 2 "graph/tree/pmormq-lowest-common-ancestor.hpp"

#line 1 "structure/others/sparse-table.hpp"
/**
 * @brief Sparse-Table(スパーステーブル)
 *
 */
template <typename T, typename F>
struct SparseTable {
  F f;
  vector<vector<T> > st;
  vector<int> lookup;

  SparseTable() = default;

  explicit SparseTable(const vector<T> &v, const F &f) : f(f) {
    const int n = (int)v.size();
    const int b = 32 - __builtin_clz(n);
    st.assign(b, vector<T>(n));
    for (int i = 0; i < v.size(); i++) {
      st[0][i] = v[i];
    }
    for (int i = 1; i < b; i++) {
      for (int j = 0; j + (1 << i) <= n; j++) {
        st[i][j] = f(st[i - 1][j], st[i - 1][j + (1 << (i - 1))]);
      }
    }
    lookup.resize(v.size() + 1);
    for (int i = 2; i < lookup.size(); i++) {
      lookup[i] = lookup[i >> 1] + 1;
    }
  }

  inline T fold(int l, int r) const {
    int b = lookup[r - l];
    return f(st[b][l], st[b][r - (1 << b)]);
  }
};

template <typename T, typename F>
SparseTable<T, F> get_sparse_table(const vector<T> &v, const F &f) {
  return SparseTable<T, F>(v, f);
}
#line 2 "structure/others/plus-minus-one-rmq.hpp"

/**
 * @brief Plus-Minus-One-RMQ
 **/
template <typename T>
struct PlusMinusOneRMQ {
  using F = function<int(int, int)>;

  int backet;
  vector<T> vs;
  vector<int> bidx, bbit;
  SparseTable<int, F> st;
  vector<vector<vector<int> > > lookup;

  explicit PlusMinusOneRMQ() = default;

  explicit PlusMinusOneRMQ(const vector<T> &vs) : vs(vs) {
    int n = (int)vs.size();
    backet = max(1, (31 - __builtin_clz(n)) / 2);
    int sz = (n + backet - 1) / backet;
    bidx.assign(sz, -1);
    bbit.assign(sz, 0);
    for (int i = 0; i < sz; i++) {
      int l = i * backet;
      int r = min(l + backet, n);
      bidx[i] = l;
      for (int j = l + 1; j < r; j++) {
        if (vs[j] < vs[bidx[i]]) bidx[i] = j;
        if (vs[j - 1] < vs[j]) bbit[i] |= 1 << (j - l - 1);
      }
    }
    F f = [&](int a, int b) { return vs[a] < vs[b] ? a : b; };
    st = get_sparse_table(bidx, f);
    lookup.assign(1 << (backet - 1),
                  vector<vector<int> >(backet, vector<int>(backet + 1)));
    for (int i = 0; i < (1 << (backet - 1)); i++) {
      for (int j = 0; j < backet; j++) {
        int sum = 0, ret = 0, pos = j;
        for (int k = j + 1; k <= backet; k++) {
          lookup[i][j][k] = pos;
          if (i & (1 << (k - 1)))
            ++sum;
          else
            --sum;
          if (sum < ret) {
            pos = k;
            ret = sum;
          }
        }
      }
    }
  }

  pair<T, int> fold(int l, int r) const {
    int lb = l / backet;
    int rb = r / backet;
    if (lb == rb) {
      int pos = lb * backet + lookup[bbit[lb]][l % backet][r % backet];
      return {vs[pos], pos};
    }
    int pos = lb * backet + lookup[bbit[lb]][l % backet][backet];
    if (r % backet > 0) {
      int sub = rb * backet + lookup[bbit[rb]][0][r % backet];
      if (vs[sub] < vs[pos]) pos = sub;
    }
    if (lb + 1 == rb) {
      return {vs[pos], pos};
    } else {
      int sub = st.fold(lb + 1, rb);
      if (vs[sub] < vs[pos]) pos = sub;
      return {vs[pos], pos};
    }
  }
};
#line 5 "graph/tree/pmormq-lowest-common-ancestor.hpp"

/**
 * @brief PMORMQ-Lowest-Common-Ancestor(最小共通祖先)
 *
 **/
template <typename T = int>
struct PMORMQLowestCommonAncestor : Graph<T> {
 public:
  using Graph<T>::Graph;
  using Graph<T>::g;
  using F = function<int(int, int)>;

  void build(int root = 0) {
    ord.reserve(g.size() * 2 - 1);
    dep.reserve(g.size() * 2 - 1);
    in.resize(g.size());
    dfs(root, -1, 0);
    vector<int> vs(g.size() * 2 - 1);
    iota(begin(vs), end(vs), 0);
    st = PlusMinusOneRMQ<int>(dep);
  }

  int lca(int x, int y) const {
    if (in[x] > in[y]) swap(x, y);
    return ord[st.fold(in[x], in[y] + 1).second];
  }

 private:
  vector<int> ord, dep, in;
  PlusMinusOneRMQ<int> st;

  void dfs(int idx, int par, int d) {
    in[idx] = (int)ord.size();
    ord.emplace_back(idx);
    dep.emplace_back(d);
    for (auto &to : g[idx]) {
      if (to != par) {
        dfs(to, idx, d + 1);
        ord.emplace_back(idx);
        dep.emplace_back(d);
      }
    }
  }
};
#line 7 "test/verify/yosupo-lca.test.cpp"

#line 1 "other/scanner.hpp"
/**
 * @brief Scanner(高速入力)
 */
struct Scanner {
 public:
  explicit Scanner(FILE *fp) : fp(fp) {}

  template <typename T, typename... E>
  void read(T &t, E &...e) {
    read_single(t);
    read(e...);
  }

 private:
  static constexpr size_t line_size = 1 << 16;
  static constexpr size_t int_digits = 20;
  char line[line_size + 1] = {};
  FILE *fp = nullptr;
  char *st = line;
  char *ed = line;

  void read() {}

  static inline bool is_space(char c) { return c <= ' '; }

  void reread() {
    ptrdiff_t len = ed - st;
    memmove(line, st, len);
    char *tmp = line + len;
    ed = tmp + fread(tmp, 1, line_size - len, fp);
    *ed = 0;
    st = line;
  }

  void skip_space() {
    while (true) {
      if (st == ed) reread();
      while (*st && is_space(*st)) ++st;
      if (st != ed) return;
    }
  }

  template <typename T, enable_if_t<is_integral<T>::value, int> = 0>
  void read_single(T &s) {
    skip_space();
    if (st + int_digits >= ed) reread();
    bool neg = false;
    if (is_signed<T>::value && *st == '-') {
      neg = true;
      ++st;
    }
    typename make_unsigned<T>::type y = *st++ - '0';
    while (*st >= '0') {
      y = 10 * y + *st++ - '0';
    }
    s = (neg ? -y : y);
  }

  template <typename T, enable_if_t<is_same<T, string>::value, int> = 0>
  void read_single(T &s) {
    s = "";
    skip_space();
    while (true) {
      char *base = st;
      while (*st && !is_space(*st)) ++st;
      s += string(base, st);
      if (st != ed) return;
      reread();
    }
  }

  template <typename T>
  void read_single(vector<T> &s) {
    for (auto &d : s) read(d);
  }
};
#line 1 "other/printer.hpp"
/**
 * @brief Printer(高速出力)
 */
struct Printer {
 public:
  explicit Printer(FILE *fp) : fp(fp) {}

  ~Printer() { flush(); }

  template <bool f = false, typename T, typename... E>
  void write(const T &t, const E &...e) {
    if (f) write_single(' ');
    write_single(t);
    write<true>(e...);
  }

  template <typename... T>
  void writeln(const T &...t) {
    write(t...);
    write_single('\n');
  }

  void flush() {
    fwrite(line, 1, st - line, fp);
    st = line;
  }

 private:
  FILE *fp = nullptr;
  static constexpr size_t line_size = 1 << 16;
  static constexpr size_t int_digits = 20;
  char line[line_size + 1] = {};
  char *st = line;

  template <bool f = false>
  void write() {}

  void write_single(const char &t) {
    if (st + 1 >= line + line_size) flush();
    *st++ = t;
  }

  template <typename T, enable_if_t<is_integral<T>::value, int> = 0>
  void write_single(T s) {
    if (st + int_digits >= line + line_size) flush();
    st += to_chars(st, st + int_digits, s).ptr - st;
  }

  void write_single(const string &s) {
    for (auto &c : s) write_single(c);
  }

  void write_single(const char *s) {
    while (*s != 0) write_single(*s++);
  }

  template <typename T>
  void write_single(const vector<T> &s) {
    for (size_t i = 0; i < s.size(); i++) {
      if (i) write_single(' ');
      write_single(s[i]);
    }
  }
};
#line 10 "test/verify/yosupo-lca.test.cpp"


int main() {
  Scanner in(stdin);
  Printer out(stdout);
  int N, Q;
  in.read(N, Q);
  PMORMQLowestCommonAncestor< int > g(N);
  for(int i = 1; i < N; i++) {
    int x;
    in.read(x);
    g.add_directed_edge(x, i);
  }
  g.build();
  for(int i = 0; i < Q; i++) {
    int u, v;
    in.read(u, v);
    out.writeln(g.lca(u, v));
  }
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	binary_00	AC	162 ms	54 MB
g++	binary_01	AC	168 ms	54 MB
g++	binary_02	AC	165 ms	54 MB
g++	example_00	AC	7 ms	4 MB
g++	line_00	AC	126 ms	82 MB
g++	line_01	AC	143 ms	97 MB
g++	line_02	AC	47 ms	14 MB
g++	line_03	AC	95 ms	90 MB
g++	line_04	AC	73 ms	59 MB
g++	max_line_00	AC	157 ms	104 MB
g++	max_line_01	AC	159 ms	104 MB
g++	max_line_02	AC	161 ms	104 MB
g++	max_random_00	AC	181 ms	54 MB
g++	max_random_01	AC	184 ms	54 MB
g++	max_random_02	AC	200 ms	54 MB
g++	path_graph_root_centroid_00	AC	124 ms	81 MB
g++	path_graph_root_centroid_01	AC	124 ms	81 MB
g++	path_graph_root_centroid_02	AC	124 ms	81 MB
g++	random_00	AC	131 ms	43 MB
g++	random_01	AC	159 ms	51 MB
g++	random_02	AC	46 ms	9 MB
g++	random_03	AC	109 ms	47 MB
g++	random_04	AC	64 ms	32 MB
clang++	binary_00	AC	193 ms	54 MB
clang++	binary_01	AC	177 ms	54 MB
clang++	binary_02	AC	186 ms	54 MB
clang++	example_00	AC	7 ms	4 MB
clang++	line_00	AC	138 ms	82 MB
clang++	line_01	AC	150 ms	97 MB
clang++	line_02	AC	53 ms	14 MB
clang++	line_03	AC	95 ms	90 MB
clang++	line_04	AC	75 ms	59 MB
clang++	max_line_00	AC	170 ms	104 MB
clang++	max_line_01	AC	172 ms	104 MB
clang++	max_line_02	AC	173 ms	104 MB
clang++	max_random_00	AC	186 ms	54 MB
clang++	max_random_01	AC	179 ms	54 MB
clang++	max_random_02	AC	193 ms	54 MB
clang++	path_graph_root_centroid_00	AC	130 ms	81 MB
clang++	path_graph_root_centroid_01	AC	132 ms	81 MB
clang++	path_graph_root_centroid_02	AC	131 ms	81 MB
clang++	random_00	AC	131 ms	43 MB
clang++	random_01	AC	161 ms	51 MB
clang++	random_02	AC	53 ms	9 MB
clang++	random_03	AC	114 ms	47 MB
clang++	random_04	AC	71 ms	32 MB

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