ds/deque_agg.hpp

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• Last update: 2024-11-09 00:49:07+00:00
• Include: #include "ds/deque_agg.hpp"

Depends on

• algebra.hpp
• prelude.hpp

Verified with

• test/ds/deque_agg.test.cpp

Code

#pragma once
#include "algebra.hpp"

template <class M>
class deque_aggregation {
 public:
  using value_type = typename M::type;
  deque_aggregation(M m = M())
      : m(m), front_cuml({m.unit()}), back_cuml({m.unit()}) {}

  void push_back(value_type v) {
    back_cuml.push_back(m.op(back_cuml.back(), v));
    back.push_back(v);
  }
  void push_front(value_type v) {
    front_cuml.push_back(m.op(v, front_cuml.back()));
    front.push_back(v);
  }
  value_type pop_front() {
    if (front.empty()) prepare_front();
    value_type res = front.back();
    front.pop_back(), front_cuml.pop_back();
    return res;
  }
  value_type pop_back() {
    if (back.empty()) prepare_back();
    value_type res = back.back();
    back.pop_back(), back_cuml.pop_back();
    return res;
  }
  value_type prod() const { return m.op(front_cuml.back(), back_cuml.back()); }

 private:
  M m;
  vector<value_type> front, front_cuml, back, back_cuml;
  void balance(int n, int m, vector<value_type> data) {
    front.clear(), front_cuml.resize(1), back.clear(), back_cuml.resize(1);
    repr(i, n) push_front(data[i]);
    rep(i, m) push_back(data[n + i]);
  }
  void prepare_front() {
    int n = (back.size() + 1) / 2;
    assert(n != 0);
    balance(n, back.size() - n, back);
  }
  void prepare_back() {
    int m = (front.size() + 1) / 2;
    assert(m != 0);
    reverse(all(front));
    balance(front.size() - m, m, front);
  }
};

#line 2 "prelude.hpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
using vc = vector<char>;
#define rep2(i, m, n) for (auto i = (m); i < (n); i++)
#define rep(i, n) rep2(i, 0, n)
#define repr2(i, m, n) for (auto i = (n); i-- > (m);)
#define repr(i, n) repr2(i, 0, n)
#define all(x) begin(x), end(x)
auto ndvec(int n, auto e) { return vector(n, e); }
auto ndvec(int n, auto ...e) { return vector(n, ndvec(e...)); }
auto comp_key(auto&& f) { return [&](auto&& a, auto&& b) { return f(a) < f(b); }; }
auto& max(const auto& a, const auto& b) { return a < b ? b : a; }
auto& min(const auto& a, const auto& b) { return b < a ? b : a; }
#if __cpp_lib_ranges
namespace R = std::ranges;
namespace V = std::views;
#endif
#line 3 "algebra.hpp"

#define CONST(val) [=] { return val; }
#define WRAP_FN(func) \
  [](auto&&... args) { return func(forward<decltype(args)>(args)...); }

template <class Unit, class Op>
struct monoid : private Unit, private Op {
  using type = decltype(declval<Unit>()());
  monoid(Unit unit, Op op) : Unit(unit), Op(op) {}
  type unit() const { return Unit::operator()(); }
  type op(type a, type b) const { return Op::operator()(a, b); }
};

template <class Unit, class Op, class Inv>
struct group : monoid<Unit, Op>, private Inv {
  using type = typename monoid<Unit, Op>::type;
  group(Unit unit, Op op, Inv inv) : monoid<Unit, Op>(unit, op), Inv(inv) {}
  type inv(type a) const { return Inv::operator()(a); }
};

template <class T>
struct addition {
  using type = T;
  type unit() const { return 0; }
  type op(type a, type b) const { return a + b; }
  type inv(type a) const { return -a; }
};

template <class T>
struct maximum {
  using type = T;
  type unit() const { return numeric_limits<T>::min(); }
  type op(type a, type b) const { return a > b ? a : b; }
};

template <class T>
struct minimum {
  using type = T;
  type unit() const { return numeric_limits<T>::max(); }
  type op(type a, type b) const { return a > b ? b : a; }
};

template <class T, T nul = -1>
struct assign {
  using type = T;
  type unit() const { return nul; }
  type op(type a, type b) const { return b == nul ? a : b; }
};
#line 3 "ds/deque_agg.hpp"

template <class M>
class deque_aggregation {
 public:
  using value_type = typename M::type;
  deque_aggregation(M m = M())
      : m(m), front_cuml({m.unit()}), back_cuml({m.unit()}) {}

  void push_back(value_type v) {
    back_cuml.push_back(m.op(back_cuml.back(), v));
    back.push_back(v);
  }
  void push_front(value_type v) {
    front_cuml.push_back(m.op(v, front_cuml.back()));
    front.push_back(v);
  }
  value_type pop_front() {
    if (front.empty()) prepare_front();
    value_type res = front.back();
    front.pop_back(), front_cuml.pop_back();
    return res;
  }
  value_type pop_back() {
    if (back.empty()) prepare_back();
    value_type res = back.back();
    back.pop_back(), back_cuml.pop_back();
    return res;
  }
  value_type prod() const { return m.op(front_cuml.back(), back_cuml.back()); }

 private:
  M m;
  vector<value_type> front, front_cuml, back, back_cuml;
  void balance(int n, int m, vector<value_type> data) {
    front.clear(), front_cuml.resize(1), back.clear(), back_cuml.resize(1);
    repr(i, n) push_front(data[i]);
    rep(i, m) push_back(data[n + i]);
  }
  void prepare_front() {
    int n = (back.size() + 1) / 2;
    assert(n != 0);
    balance(n, back.size() - n, back);
  }
  void prepare_back() {
    int m = (front.size() + 1) / 2;
    assert(m != 0);
    reverse(all(front));
    balance(front.size() - m, m, front);
  }
};

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