utility/revrep.cpp

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• Last update: 2021-12-17 09:20:39+09:00

Required by

• algorithm/convolution_arbitrary_mod.cpp
• algorithm/convolution_int.cpp
• algorithm/convolution_mod.cpp
• container/dual_segment_tree.cpp
• container/lazy_segment_tree.cpp
• container/segment_tree.cpp
• container/segment_tree_beats.cpp
• graph/re_rooting.cpp
• internal/modulo_transform.cpp
• utility/fast_io.cpp

Verified with

• test/convolution_arbitrary_mod.test.cpp
• test/convolution_mod.test.cpp
• test/dual_segment_tree.test.cpp
• test/fast_io.test.cpp
• test/heavy_light_decomposition.test.cpp
• test/larsch.test.cpp
• test/lazy_segment_tree.test.cpp
• test/segment_tree.test.cpp
• test/segment_tree_beats.test.cpp

Code

#pragma once
#include <algorithm>

class ReversedRange {
    struct Iter {
        int itr;
        constexpr Iter(const int pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { --itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr int operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr ReversedRange(const int first, const int last) noexcept
        : first(last - 1), last(std::min(first, last) - 1) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

constexpr ReversedRange revrep(const int l, const int r) noexcept { return ReversedRange(l, r); }
constexpr ReversedRange revrep(const int n) noexcept { return ReversedRange(0, n); }

#line 2 "utility/revrep.cpp"
#include <algorithm>

class ReversedRange {
    struct Iter {
        int itr;
        constexpr Iter(const int pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { --itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr int operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr ReversedRange(const int first, const int last) noexcept
        : first(last - 1), last(std::min(first, last) - 1) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

constexpr ReversedRange revrep(const int l, const int r) noexcept { return ReversedRange(l, r); }
constexpr ReversedRange revrep(const int n) noexcept { return ReversedRange(0, n); }

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