Problem p02710 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

using i32 = int_fast32_t;
using i64 = int_fast64_t;
using u32 = uint_fast32_t;
using u64 = uint_fast64_t;
using f64 = double;
using f80 = long double;

#define FOR(v, a, b) for (i64 v = (a); v < (b); ++v)
#define FORE(v, a, b) for (i64 v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for (i64 v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for (auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for (auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c, x) ((c).find(x) != (c).end())
#define fst first
#define snd second
#define UNIQ(v) (v).erase(unique(ALL(v)), (v).end())
#define bit(i) (1LL << (i))

#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...) ((void)0)
#endif

using namespace std;

template <typename I> void join(ostream &ost, I s, I t, string d = " ") {
  for (auto i = s; i != t; ++i) {
    if (i != s)
      ost << d;
    ost << *i;
  }
  ost << endl;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <typename T> void pout(const T &value) { std::cout << value << "\\n"; }
template <typename T, typename... Args>
void pout(const T &value, const Args &...args) {
  std::cout << value << " ";
  pout(args...);
}

template <typename T, typename U> bool chmin(T &a, const U &b) {
  return (a > b ? a = b, true : false);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  return (a < b ? a = b, true : false);
}
template <typename T, size_t N, typename U>
void fill_array(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}
template <typename T> auto make_vector(int n, int m, const T &value) {
  return vector<vector<T>>(n, vector<T>(m, value));
}

struct Init {
  Init() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(12);
  }
} init;

template <typename Cost = int> class Edge {
public:
  int from, to;
  Cost cost;
  Edge() {}
  Edge(int to, Cost cost) : to(to), cost(cost) {}
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost) {}

  Edge rev() const { return Edge(to, from, cost); }

  friend std::ostream &operator<<(std::ostream &os, const Edge &e) {
    os << "(FROM: " << e.from << ","
       << "TO: " << e.to << ","
       << "COST: " << e.cost << ")";
    return os;
  }
};

template <typename T> using Graph = std::vector<std::vector<Edge<T>>>;
template <typename T> using Tree = std::vector<std::vector<Edge<T>>>;

template <typename C, typename T> void add_edge(C &g, int from, int to, T w) {
  g[from].emplace_back(from, to, w);
}

template <typename C, typename T> void add_undirected(C &g, int a, int b, T w) {
  add_edge(g, a, b, w);
  add_edge(g, b, a, w);
}

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

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

template <typename F>
static inline constexpr decltype(auto) make_fix_point(F &&f) {
  return FixPoint<F>(std::forward<F>(f));
}

template <typename F>
static inline constexpr decltype(auto) make_fix_point(F &f) {
  return FixPoint<F>(std::forward<F>(f));
}

int main() {
  int N;

  while (cin >> N) {
    vector<int> c(N);
    cin >> c;
    REP(i, N) c[i] -= 1;

    Tree<int> tree(N);
    REP(i, N - 1) {
      int a, b;
      cin >> a >> b;
      --a, --b;
      add_undirected(tree, a, b, 1);
    }

    vector<int> s(N);

    {
      auto f = [&](auto &&f, int cur, int par = -1) -> int {
        s[cur] = 1;

        for (auto &e : tree[cur]) {
          if (e.to == par)
            continue;
          s[cur] += f(e.to, cur);
        }

        return s[cur];
      };
      make_fix_point(f)(0);
    }

    dump(s);

    vector<pair<int, int>> nearest(N, make_pair(-1, -1));
    {
      map<int, vector<pair<int, int>>> m;

      auto f = [&](auto &&f, int cur, int par = -1) -> void {
        if (m[c[cur]].size())
          nearest[cur] = m[c[cur]].back();

        REP(i, tree[cur].size()) {
          auto &e = tree[cur][i];
          if (e.to == par)
            continue;
          m[c[cur]].emplace_back(cur, i);
          f(e.to, cur);
          m[c[cur]].pop_back();
        }
      };

      make_fix_point(f)(0);

      dump(nearest);
    }

    vector<vector<vector<int>>> desc(N);
    REP(i, N) desc[i].resize(tree[i].size());
    REP(i, N) {
      if (nearest[i] != make_pair(-1, -1)) {
        desc[nearest[i].fst][nearest[i].snd].push_back(i);
      }
    }

    vector<i64> ans(N);
    auto calc = [](i64 n) { return n * (n - 1) / 2 + n; };

    {
      auto f = [&](auto &&f, int cur, int par = -1) -> void {
        REP(i, tree[cur].size()) {
          auto &e = tree[cur][i];
          if (e.to == par)
            continue;

          f(e.to, cur);

          auto t = s[e.to];
          for (auto j : desc[cur][i]) {
            t -= s[j];
          }
          ans[c[cur]] += calc(t);
        }
      };

      make_fix_point(f)(0);

      vector<int> a(N, s[0]);
      REP(i, N) {
        if (nearest[i] == make_pair(-1, -1))
          a[c[i]] -= s[i];
      }
      REP(i, N) { ans[i] += calc(a[i]); }
    }

    dump(ans);

    REP(i, N) ans[i] = calc(N) - ans[i];

    join(cout, ALL(ans), "\\n");
    cerr << "\\n";
  }

  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>

using i32 = int_fast32_t;
using i64 = int_fast64_t;
using u32 = uint_fast32_t;
using u64 = uint_fast64_t;
using f64 = double;
using f80 = long double;

#define FOR(v, a, b) for (i64 v = (a); v < (b); ++v)
#define FORE(v, a, b) for (i64 v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for (i64 v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for (auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for (auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c, x) ((c).find(x) != (c).end())
#define fst first
#define snd second
#define UNIQ(v) (v).erase(unique(ALL(v)), (v).end())
#define bit(i) (1LL << (i))

#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...) ((void)0)
#endif

using namespace std;

template <typename I> void join(ostream &ost, I s, I t, string d = " ") {
  for (auto i = s; i != t; ++i) {
    if (i != s)
      ost << d;
    ost << *i;
  }
  ost << endl;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <typename T> void pout(const T &value) { std::cout << value << "\\n"; }
template <typename T, typename... Args>
void pout(const T &value, const Args &...args) {
  std::cout << value << " ";
  pout(args...);
}

template <typename T, typename U> bool chmin(T &a, const U &b) {
  return (a > b ? a = b, true : false);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  return (a < b ? a = b, true : false);
}
template <typename T, size_t N, typename U>
void fill_array(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}
template <typename T> auto make_vector(int n, int m, const T &value) {
  return vector<vector<T>>(n, vector<T>(m, value));
}

struct Init {
  Init() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(12);
  }
} init;

template <typename Cost = int> class Edge {
public:
  int from, to;
  Cost cost;
  Edge() {}
  Edge(int to, Cost cost) : to(to), cost(cost) {}
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost) {}

  Edge rev() const { return Edge(to, from, cost); }

  friend std::ostream &operator<<(std::ostream &os, const Edge &e) {
    os << "(FROM: " << e.from << ","
       << "TO: " << e.to << ","
       << "COST: " << e.cost << ")";
    return os;
  }
};

template <typename T> using Graph = std::vector<std::vector<Edge<T>>>;
template <typename T> using Tree = std::vector<std::vector<Edge<T>>>;

template <typename C, typename T> void add_edge(C &g, int from, int to, T w) {
  g[from].emplace_back(from, to, w);
}

template <typename C, typename T> void add_undirected(C &g, int a, int b, T w) {
  add_edge(g, a, b, w);
  add_edge(g, b, a, w);
}

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

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

template <typename F>
static inline constexpr decltype(auto) make_fix_point(F &&f) {
  return FixPoint<F>(std::forward<F>(f));
}

template <typename F>
static inline constexpr decltype(auto) make_fix_point(F &f) {
  return FixPoint<F>(std::forward<F>(f));
}

int main() {
  int N;

  while (cin >> N) {
    vector<int> c(N);
    cin >> c;
    REP(i, N) c[i] -= 1;

    Tree<int> tree(N);
    REP(i, N - 1) {
      int a, b;
      cin >> a >> b;
      --a, --b;
      add_undirected(tree, a, b, 1);
    }

    vector<int> s(N);

    {
      auto f = [&](auto &&f, int cur, int par = -1) -> int {
        s[cur] = 1;

        for (auto &e : tree[cur]) {
          if (e.to == par)
            continue;
          s[cur] += f(e.to, cur);
        }

        return s[cur];
      };
      make_fix_point(f)(0);
    }

    dump(s);

    vector<i64> ans(N);
    auto calc = [](i64 n) { return n * (n - 1) / 2 + n; };

    {
      vector<map<int, i64>> m(N);

      auto f = [&](auto &&f, int cur, int par = -1) -> void {
        for (auto &e : tree[cur]) {
          if (e.to == par)
            continue;

          f(e.to, cur);

          auto t = s[e.to] - m[e.to][c[cur]];
          // dump(make_pair(e.to, t));
          ans[c[cur]] += calc(t);

          for (auto &[k, v] : m[e.to]) {
            m[cur][k] += v;
          }
        }

        m[cur][c[cur]] = s[cur];
      };

      make_fix_point(f)(0);

      REP(i, N) {
        if (c[0] != i) {
          auto t = s[0] - m[0][i];
          ans[i] += calc(t);
        }
      }
    }

    dump(ans);

    REP(i, N) ans[i] = calc(N) - ans[i];

    join(cout, ALL(ans), "\\n");
    cerr << "\\n";
  }

  return 0;
}