diff --git a/lemon/radix_sort.h b/lemon/radix_sort.h --- a/lemon/radix_sort.h +++ b/lemon/radix_sort.h @@ -1,6 +1,6 @@ -/* -*- C++ -*- +/* -*- mode: C++; indent-tabs-mode: nil; -*- * - * This file is a part of LEMON, a generic C++ optimization library + * This file is a part of LEMON, a generic C++ optimization library. * * Copyright (C) 2003-2008 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport @@ -37,93 +37,93 @@ template struct Identity { const Value& operator()(const Value& val) { - return val; + return val; } }; template - Iterator radixSortPartition(Iterator first, Iterator last, - Functor functor, Value mask) { + Iterator radixSortPartition(Iterator first, Iterator last, + Functor functor, Value mask) { while (first != last && !(functor(*first) & mask)) { - ++first; + ++first; } if (first == last) { - return first; + return first; } --last; while (first != last && (functor(*last) & mask)) { - --last; + --last; } if (first == last) { - return first; + return first; } std::iter_swap(first, last); ++first; if (!(first < last)) { - return first; + return first; } while (true) { - while (!(functor(*first) & mask)) { - ++first; - } - --last; - while (functor(*last) & mask) { - --last; - } - if (!(first < last)) { - return first; - } - std::iter_swap(first, last); - ++first; + while (!(functor(*first) & mask)) { + ++first; + } + --last; + while (functor(*last) & mask) { + --last; + } + if (!(first < last)) { + return first; + } + std::iter_swap(first, last); + ++first; } } template - Iterator radixSortSignPartition(Iterator first, Iterator last, - Functor functor) { + Iterator radixSortSignPartition(Iterator first, Iterator last, + Functor functor) { while (first != last && functor(*first) < 0) { - ++first; + ++first; } if (first == last) { - return first; + return first; } --last; while (first != last && functor(*last) >= 0) { - --last; + --last; } if (first == last) { - return first; + return first; } std::iter_swap(first, last); ++first; if (!(first < last)) { - return first; + return first; } while (true) { - while (functor(*first) < 0) { - ++first; - } - --last; - while (functor(*last) >= 0) { - --last; - } - if (!(first < last)) { - return first; - } - std::iter_swap(first, last); - ++first; + while (functor(*first) < 0) { + ++first; + } + --last; + while (functor(*last) >= 0) { + --last; + } + if (!(first < last)) { + return first; + } + std::iter_swap(first, last); + ++first; } } template - void radixIntroSort(Iterator first, Iterator last, - Functor functor, Value mask) { + void radixIntroSort(Iterator first, Iterator last, + Functor functor, Value mask) { while (mask != 0 && last - first > 1) { - Iterator cut = radixSortPartition(first, last, functor, mask); - mask >>= 1; - radixIntroSort(first, cut, functor, mask); - first = cut; + Iterator cut = radixSortPartition(first, last, functor, mask); + mask >>= 1; + radixIntroSort(first, cut, functor, mask); + first = cut; } } @@ -138,19 +138,19 @@ mask = ~0; max_digit = 0; for (it = first; it != cut; ++it) { - while ((mask & functor(*it)) != mask) { - ++max_digit; - mask <<= 1; - } + while ((mask & functor(*it)) != mask) { + ++max_digit; + mask <<= 1; + } } radixIntroSort(first, cut, functor, 1 << max_digit); mask = 0; max_digit = 0; for (it = cut; it != last; ++it) { - while ((mask | functor(*it)) != mask) { - ++max_digit; - mask <<= 1; mask |= 1; - } + while ((mask | functor(*it)) != mask) { + ++max_digit; + mask <<= 1; mask |= 1; + } } radixIntroSort(cut, last, functor, 1 << max_digit); } @@ -163,21 +163,21 @@ Iterator it; for (it = first; it != last; ++it) { - while ((mask | functor(*it)) != mask) { - ++max_digit; - mask <<= 1; mask |= 1; - } + while ((mask | functor(*it)) != mask) { + ++max_digit; + mask <<= 1; mask |= 1; + } } radixIntroSort(first, last, functor, 1 << max_digit); } - template ::is_signed > + template ::is_signed > struct RadixSortSelector { template static void sort(Iterator first, Iterator last, Functor functor) { - radixSignedSort(first, last, functor); + radixSignedSort(first, last, functor); } }; @@ -185,7 +185,7 @@ struct RadixSortSelector { template static void sort(Iterator first, Iterator last, Functor functor) { - radixUnsignedSort(first, last, functor); + radixUnsignedSort(first, last, functor); } }; @@ -195,26 +195,29 @@ /// /// \brief Sorts the STL compatible range into ascending order. /// - /// The \c radixSort sorts the STL compatible range into ascending - /// order. The radix sort algorithm can sort the items which mapped - /// to an integer with an adaptable unary function \c functor and the - /// order will be ascending by these mapped values. As function - /// specialization it is possible to use a normal function instead - /// of the functor object or if the functor is not given it will use - /// an identity function instead. + /// The \c radixSort sorts an STL compatible range into ascending + /// order. The radix sort algorithm can sort items which are mapped + /// to integers with an adaptable unary function \c functor and the + /// order will be ascending according to these mapped values. /// - /// This implemented radix sort is a special quick sort which pivot - /// value is choosen to partite the items on the next - /// bit. Therefore, let be \c c the maximal capacity and \c n the - /// number of the items in the container, the time complexity of the - /// algorithm is \f$ O(\log(c)n) \f$ and the additional space - /// complexity is \f$ O(\log(c)) \f$. + /// It is also possible to use a normal function instead + /// of the functor object. If the functor is not given it will use + /// the identity function instead. + /// + /// This is a special quick sort algorithm where the pivot + /// values to split the items are choosen to be \f$ 2^k \f$ for each \c k. + /// Therefore, the time complexity of the + /// algorithm is \f$ O(\log(c)n) \f$ and it uses \f$ O(\log(c)) \f$, + /// additional space, where \c c is the maximal value and \c n is the + /// number of the items in the container. /// /// \param first The begin of the given range. /// \param last The end of the given range. /// \param functor An adaptible unary function or a normal function /// which maps the items to any integer type which can be either /// signed or unsigned. + /// + /// \sa counterSort() template void radixSort(Iterator first, Iterator last, Functor functor) { using namespace _radix_sort_bits; @@ -261,63 +264,63 @@ } template - void counterIntroSort(Key *first, Key *last, Key *target, - int byte, Functor functor) { - const int size = - unsigned(std::numeric_limits::max()) + 1; + void counterIntroSort(Key *first, Key *last, Key *target, + int byte, Functor functor) { + const int size = + unsigned(std::numeric_limits::max()) + 1; std::vector counter(size); for (int i = 0; i < size; ++i) { - counter[i] = 0; + counter[i] = 0; } Key *it = first; while (first != last) { - ++counter[valueByte(functor(*first), byte)]; - ++first; + ++counter[valueByte(functor(*first), byte)]; + ++first; } int prev, num = 0; for (int i = 0; i < size; ++i) { - prev = num; - num += counter[i]; - counter[i] = prev; + prev = num; + num += counter[i]; + counter[i] = prev; } while (it != last) { - target[counter[valueByte(functor(*it), byte)]++] = *it; - ++it; + target[counter[valueByte(functor(*it), byte)]++] = *it; + ++it; } } template - void signedCounterIntroSort(Key *first, Key *last, Key *target, - int byte, Functor functor) { - const int size = - unsigned(std::numeric_limits::max()) + 1; + void signedCounterIntroSort(Key *first, Key *last, Key *target, + int byte, Functor functor) { + const int size = + unsigned(std::numeric_limits::max()) + 1; std::vector counter(size); for (int i = 0; i < size; ++i) { - counter[i] = 0; + counter[i] = 0; } Key *it = first; while (first != last) { - counter[valueByte(functor(*first), byte)]++; - ++first; + counter[valueByte(functor(*first), byte)]++; + ++first; } int prev, num = 0; for (int i = size / 2; i < size; ++i) { - prev = num; - num += counter[i]; - counter[i] = prev; + prev = num; + num += counter[i]; + counter[i] = prev; } for (int i = 0; i < size / 2; ++i) { - prev = num; - num += counter[i]; - counter[i] = prev; + prev = num; + num += counter[i]; + counter[i] = prev; } while (it != last) { - target[counter[valueByte(functor(*it), byte)]++] = *it; - ++it; + target[counter[valueByte(functor(*it), byte)]++] = *it; + ++it; } } - + template void counterSignedSort(Iterator first, Iterator last, Functor functor) { if (first == last) return; @@ -328,30 +331,30 @@ int length = std::distance(first, last); Key* buffer = allocator.allocate(2 * length); try { - bool dir = true; - std::copy(first, last, buffer); - for (int i = 0; i < int(sizeof(Value)) - 1; ++i) { - if (dir) { - counterIntroSort(buffer, buffer + length, buffer + length, - i, functor); - } else { - counterIntroSort(buffer + length, buffer + 2 * length, buffer, - i, functor); - } - dir = !dir; - } - if (dir) { - signedCounterIntroSort(buffer, buffer + length, buffer + length, - sizeof(Value) - 1, functor); - std::copy(buffer + length, buffer + 2 * length, first); - } else { - signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer, - sizeof(Value) - 1, functor); - std::copy(buffer, buffer + length, first); - } + bool dir = true; + std::copy(first, last, buffer); + for (int i = 0; i < int(sizeof(Value)) - 1; ++i) { + if (dir) { + counterIntroSort(buffer, buffer + length, buffer + length, + i, functor); + } else { + counterIntroSort(buffer + length, buffer + 2 * length, buffer, + i, functor); + } + dir = !dir; + } + if (dir) { + signedCounterIntroSort(buffer, buffer + length, buffer + length, + sizeof(Value) - 1, functor); + std::copy(buffer + length, buffer + 2 * length, first); + } else { + signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer, + sizeof(Value) - 1, functor); + std::copy(buffer, buffer + length, first); + } } catch (...) { - allocator.deallocate(buffer, 2 * length); - throw; + allocator.deallocate(buffer, 2 * length); + throw; } allocator.deallocate(buffer, 2 * length); } @@ -366,38 +369,38 @@ int length = std::distance(first, last); Key *buffer = allocator.allocate(2 * length); try { - bool dir = true; - std::copy(first, last, buffer); - for (int i = 0; i < int(sizeof(Value)); ++i) { - if (dir) { - counterIntroSort(buffer, buffer + length, - buffer + length, i, functor); - } else { - counterIntroSort(buffer + length, buffer + 2 * length, - buffer, i, functor); - } - dir = !dir; - } - if (dir) { - std::copy(buffer, buffer + length, first); - } else { - std::copy(buffer + length, buffer + 2 * length, first); - } + bool dir = true; + std::copy(first, last, buffer); + for (int i = 0; i < int(sizeof(Value)); ++i) { + if (dir) { + counterIntroSort(buffer, buffer + length, + buffer + length, i, functor); + } else { + counterIntroSort(buffer + length, buffer + 2 * length, + buffer, i, functor); + } + dir = !dir; + } + if (dir) { + std::copy(buffer, buffer + length, first); + } else { + std::copy(buffer + length, buffer + 2 * length, first); + } } catch (...) { - allocator.deallocate(buffer, 2 * length); - throw; + allocator.deallocate(buffer, 2 * length); + throw; } allocator.deallocate(buffer, 2 * length); } - template ::is_signed > + template ::is_signed > struct CounterSortSelector { template static void sort(Iterator first, Iterator last, Functor functor) { - counterSignedSort(first, last, functor); + counterSignedSort(first, last, functor); } }; @@ -405,7 +408,7 @@ struct CounterSortSelector { template static void sort(Iterator first, Iterator last, Functor functor) { - counterUnsignedSort(first, last, functor); + counterUnsignedSort(first, last, functor); } }; @@ -413,34 +416,33 @@ /// \ingroup auxalg /// - /// \brief Sorts stable the STL compatible range into ascending order. + /// \brief Sorts the STL compatible range into ascending order in a stable + /// way. /// - /// The \c counterSort sorts the STL compatible range into ascending - /// order. The counter sort algorithm can sort the items which - /// mapped to an integer with an adaptable unary function \c functor - /// and the order will be ascending by these mapped values. As - /// function specialization it is possible to use a normal function - /// instead of the functor object or if the functor is not given it - /// will use an identity function instead. + /// This function sorts an STL compatible range into ascending + /// order according to an integer mapping in the same as radixSort() does. /// - /// The implemented counter sort use a radix forward sort on the + /// This sorting algorithm is stable, i.e. the order of two equal + /// element remains the same after the sorting. + /// + /// This sort algorithm use a radix forward sort on the /// bytes of the integer number. The algorithm sorts the items - /// byte-by-byte, first it counts how many times occurs a byte value - /// in the containerm, and with the occurence number the container - /// can be copied to an other in asceding order in \c O(n) time. - /// Let be \c c the maximal capacity of the integer type and \c n - /// the number of the items in the container, the time complexity of - /// the algorithm is \f$ O(\log(c)n) \f$ and the additional space - /// complexity is \f$ O(n) \f$. + /// byte-by-byte. First, it counts how many times a byte value occurs + /// in the container, then it copies the corresponding items to + /// another container in asceding order in \c O(n) time. /// - /// The sorting algorithm is stable, i.e. the order of two equal - /// element remains the same. + /// The time complexity of the algorithm is \f$ O(\log(c)n) \f$ and + /// it uses \f$ O(n) \f$, additional space, where \c c is the + /// maximal value and \c n is the number of the items in the + /// container. /// + /// \param first The begin of the given range. /// \param last The end of the given range. /// \param functor An adaptible unary function or a normal function /// which maps the items to any integer type which can be either /// signed or unsigned. + /// \sa radixSort() template void counterSort(Iterator first, Iterator last, Functor functor) { using namespace _radix_sort_bits; diff --git a/test/radix_sort_test.cc b/test/radix_sort_test.cc --- a/test/radix_sort_test.cc +++ b/test/radix_sort_test.cc @@ -1,6 +1,6 @@ -/* -*- C++ -*- +/* -*- mode: C++; indent-tabs-mode: nil; -*- * - * This file is a part of LEMON, a generic C++ optimization library + * This file is a part of LEMON, a generic C++ optimization library. * * Copyright (C) 2003-2008 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport @@ -81,8 +81,8 @@ check(data1[i] == data2[n - 1 - i], "Test failed"); } - } - + } + { std::vector data1(n); generateCharSequence(n, data1); @@ -121,7 +121,7 @@ for (int i = 0; i < n; ++i) { check(data1[i] == data2[n - 1 - i], "Test failed"); } - } + } { std::vector data1(n); @@ -140,7 +140,7 @@ int main() { - checkRadixSort(); + checkRadixSort(); checkCounterSort(); return 0;