1.1 --- a/lemon/radix_sort.h Fri Oct 17 23:55:18 2008 +0200
1.2 +++ b/lemon/radix_sort.h Tue Dec 02 10:17:30 2008 +0000
1.3 @@ -1,6 +1,6 @@
1.4 -/* -*- C++ -*-
1.5 +/* -*- mode: C++; indent-tabs-mode: nil; -*-
1.6 *
1.7 - * This file is a part of LEMON, a generic C++ optimization library
1.8 + * This file is a part of LEMON, a generic C++ optimization library.
1.9 *
1.10 * Copyright (C) 2003-2008
1.11 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.12 @@ -37,93 +37,93 @@
1.13 template <typename Value>
1.14 struct Identity {
1.15 const Value& operator()(const Value& val) {
1.16 - return val;
1.17 + return val;
1.18 }
1.19 };
1.20
1.21
1.22 template <typename Value, typename Iterator, typename Functor>
1.23 - Iterator radixSortPartition(Iterator first, Iterator last,
1.24 - Functor functor, Value mask) {
1.25 + Iterator radixSortPartition(Iterator first, Iterator last,
1.26 + Functor functor, Value mask) {
1.27 while (first != last && !(functor(*first) & mask)) {
1.28 - ++first;
1.29 + ++first;
1.30 }
1.31 if (first == last) {
1.32 - return first;
1.33 + return first;
1.34 }
1.35 --last;
1.36 while (first != last && (functor(*last) & mask)) {
1.37 - --last;
1.38 + --last;
1.39 }
1.40 if (first == last) {
1.41 - return first;
1.42 + return first;
1.43 }
1.44 std::iter_swap(first, last);
1.45 ++first;
1.46 if (!(first < last)) {
1.47 - return first;
1.48 + return first;
1.49 }
1.50 while (true) {
1.51 - while (!(functor(*first) & mask)) {
1.52 - ++first;
1.53 - }
1.54 - --last;
1.55 - while (functor(*last) & mask) {
1.56 - --last;
1.57 - }
1.58 - if (!(first < last)) {
1.59 - return first;
1.60 - }
1.61 - std::iter_swap(first, last);
1.62 - ++first;
1.63 + while (!(functor(*first) & mask)) {
1.64 + ++first;
1.65 + }
1.66 + --last;
1.67 + while (functor(*last) & mask) {
1.68 + --last;
1.69 + }
1.70 + if (!(first < last)) {
1.71 + return first;
1.72 + }
1.73 + std::iter_swap(first, last);
1.74 + ++first;
1.75 }
1.76 }
1.77
1.78 template <typename Iterator, typename Functor>
1.79 - Iterator radixSortSignPartition(Iterator first, Iterator last,
1.80 - Functor functor) {
1.81 + Iterator radixSortSignPartition(Iterator first, Iterator last,
1.82 + Functor functor) {
1.83 while (first != last && functor(*first) < 0) {
1.84 - ++first;
1.85 + ++first;
1.86 }
1.87 if (first == last) {
1.88 - return first;
1.89 + return first;
1.90 }
1.91 --last;
1.92 while (first != last && functor(*last) >= 0) {
1.93 - --last;
1.94 + --last;
1.95 }
1.96 if (first == last) {
1.97 - return first;
1.98 + return first;
1.99 }
1.100 std::iter_swap(first, last);
1.101 ++first;
1.102 if (!(first < last)) {
1.103 - return first;
1.104 + return first;
1.105 }
1.106 while (true) {
1.107 - while (functor(*first) < 0) {
1.108 - ++first;
1.109 - }
1.110 - --last;
1.111 - while (functor(*last) >= 0) {
1.112 - --last;
1.113 - }
1.114 - if (!(first < last)) {
1.115 - return first;
1.116 - }
1.117 - std::iter_swap(first, last);
1.118 - ++first;
1.119 + while (functor(*first) < 0) {
1.120 + ++first;
1.121 + }
1.122 + --last;
1.123 + while (functor(*last) >= 0) {
1.124 + --last;
1.125 + }
1.126 + if (!(first < last)) {
1.127 + return first;
1.128 + }
1.129 + std::iter_swap(first, last);
1.130 + ++first;
1.131 }
1.132 }
1.133
1.134 template <typename Value, typename Iterator, typename Functor>
1.135 - void radixIntroSort(Iterator first, Iterator last,
1.136 - Functor functor, Value mask) {
1.137 + void radixIntroSort(Iterator first, Iterator last,
1.138 + Functor functor, Value mask) {
1.139 while (mask != 0 && last - first > 1) {
1.140 - Iterator cut = radixSortPartition(first, last, functor, mask);
1.141 - mask >>= 1;
1.142 - radixIntroSort(first, cut, functor, mask);
1.143 - first = cut;
1.144 + Iterator cut = radixSortPartition(first, last, functor, mask);
1.145 + mask >>= 1;
1.146 + radixIntroSort(first, cut, functor, mask);
1.147 + first = cut;
1.148 }
1.149 }
1.150
1.151 @@ -138,19 +138,19 @@
1.152
1.153 mask = ~0; max_digit = 0;
1.154 for (it = first; it != cut; ++it) {
1.155 - while ((mask & functor(*it)) != mask) {
1.156 - ++max_digit;
1.157 - mask <<= 1;
1.158 - }
1.159 + while ((mask & functor(*it)) != mask) {
1.160 + ++max_digit;
1.161 + mask <<= 1;
1.162 + }
1.163 }
1.164 radixIntroSort(first, cut, functor, 1 << max_digit);
1.165
1.166 mask = 0; max_digit = 0;
1.167 for (it = cut; it != last; ++it) {
1.168 - while ((mask | functor(*it)) != mask) {
1.169 - ++max_digit;
1.170 - mask <<= 1; mask |= 1;
1.171 - }
1.172 + while ((mask | functor(*it)) != mask) {
1.173 + ++max_digit;
1.174 + mask <<= 1; mask |= 1;
1.175 + }
1.176 }
1.177 radixIntroSort(cut, last, functor, 1 << max_digit);
1.178 }
1.179 @@ -163,21 +163,21 @@
1.180
1.181 Iterator it;
1.182 for (it = first; it != last; ++it) {
1.183 - while ((mask | functor(*it)) != mask) {
1.184 - ++max_digit;
1.185 - mask <<= 1; mask |= 1;
1.186 - }
1.187 + while ((mask | functor(*it)) != mask) {
1.188 + ++max_digit;
1.189 + mask <<= 1; mask |= 1;
1.190 + }
1.191 }
1.192 radixIntroSort(first, last, functor, 1 << max_digit);
1.193 }
1.194
1.195
1.196 - template <typename Value,
1.197 - bool sign = std::numeric_limits<Value>::is_signed >
1.198 + template <typename Value,
1.199 + bool sign = std::numeric_limits<Value>::is_signed >
1.200 struct RadixSortSelector {
1.201 template <typename Iterator, typename Functor>
1.202 static void sort(Iterator first, Iterator last, Functor functor) {
1.203 - radixSignedSort<Value>(first, last, functor);
1.204 + radixSignedSort<Value>(first, last, functor);
1.205 }
1.206 };
1.207
1.208 @@ -185,7 +185,7 @@
1.209 struct RadixSortSelector<Value, false> {
1.210 template <typename Iterator, typename Functor>
1.211 static void sort(Iterator first, Iterator last, Functor functor) {
1.212 - radixUnsignedSort<Value>(first, last, functor);
1.213 + radixUnsignedSort<Value>(first, last, functor);
1.214 }
1.215 };
1.216
1.217 @@ -195,26 +195,29 @@
1.218 ///
1.219 /// \brief Sorts the STL compatible range into ascending order.
1.220 ///
1.221 - /// The \c radixSort sorts the STL compatible range into ascending
1.222 - /// order. The radix sort algorithm can sort the items which mapped
1.223 - /// to an integer with an adaptable unary function \c functor and the
1.224 - /// order will be ascending by these mapped values. As function
1.225 - /// specialization it is possible to use a normal function instead
1.226 - /// of the functor object or if the functor is not given it will use
1.227 - /// an identity function instead.
1.228 + /// The \c radixSort sorts an STL compatible range into ascending
1.229 + /// order. The radix sort algorithm can sort items which are mapped
1.230 + /// to integers with an adaptable unary function \c functor and the
1.231 + /// order will be ascending according to these mapped values.
1.232 ///
1.233 - /// This implemented radix sort is a special quick sort which pivot
1.234 - /// value is choosen to partite the items on the next
1.235 - /// bit. Therefore, let be \c c the maximal capacity and \c n the
1.236 - /// number of the items in the container, the time complexity of the
1.237 - /// algorithm is \f$ O(\log(c)n) \f$ and the additional space
1.238 - /// complexity is \f$ O(\log(c)) \f$.
1.239 + /// It is also possible to use a normal function instead
1.240 + /// of the functor object. If the functor is not given it will use
1.241 + /// the identity function instead.
1.242 + ///
1.243 + /// This is a special quick sort algorithm where the pivot
1.244 + /// values to split the items are choosen to be \f$ 2^k \f$ for each \c k.
1.245 + /// Therefore, the time complexity of the
1.246 + /// algorithm is \f$ O(\log(c)n) \f$ and it uses \f$ O(\log(c)) \f$,
1.247 + /// additional space, where \c c is the maximal value and \c n is the
1.248 + /// number of the items in the container.
1.249 ///
1.250 /// \param first The begin of the given range.
1.251 /// \param last The end of the given range.
1.252 /// \param functor An adaptible unary function or a normal function
1.253 /// which maps the items to any integer type which can be either
1.254 /// signed or unsigned.
1.255 + ///
1.256 + /// \sa counterSort()
1.257 template <typename Iterator, typename Functor>
1.258 void radixSort(Iterator first, Iterator last, Functor functor) {
1.259 using namespace _radix_sort_bits;
1.260 @@ -261,63 +264,63 @@
1.261 }
1.262
1.263 template <typename Functor, typename Key>
1.264 - void counterIntroSort(Key *first, Key *last, Key *target,
1.265 - int byte, Functor functor) {
1.266 - const int size =
1.267 - unsigned(std::numeric_limits<unsigned char>::max()) + 1;
1.268 + void counterIntroSort(Key *first, Key *last, Key *target,
1.269 + int byte, Functor functor) {
1.270 + const int size =
1.271 + unsigned(std::numeric_limits<unsigned char>::max()) + 1;
1.272 std::vector<int> counter(size);
1.273 for (int i = 0; i < size; ++i) {
1.274 - counter[i] = 0;
1.275 + counter[i] = 0;
1.276 }
1.277 Key *it = first;
1.278 while (first != last) {
1.279 - ++counter[valueByte(functor(*first), byte)];
1.280 - ++first;
1.281 + ++counter[valueByte(functor(*first), byte)];
1.282 + ++first;
1.283 }
1.284 int prev, num = 0;
1.285 for (int i = 0; i < size; ++i) {
1.286 - prev = num;
1.287 - num += counter[i];
1.288 - counter[i] = prev;
1.289 + prev = num;
1.290 + num += counter[i];
1.291 + counter[i] = prev;
1.292 }
1.293 while (it != last) {
1.294 - target[counter[valueByte(functor(*it), byte)]++] = *it;
1.295 - ++it;
1.296 + target[counter[valueByte(functor(*it), byte)]++] = *it;
1.297 + ++it;
1.298 }
1.299 }
1.300
1.301 template <typename Functor, typename Key>
1.302 - void signedCounterIntroSort(Key *first, Key *last, Key *target,
1.303 - int byte, Functor functor) {
1.304 - const int size =
1.305 - unsigned(std::numeric_limits<unsigned char>::max()) + 1;
1.306 + void signedCounterIntroSort(Key *first, Key *last, Key *target,
1.307 + int byte, Functor functor) {
1.308 + const int size =
1.309 + unsigned(std::numeric_limits<unsigned char>::max()) + 1;
1.310 std::vector<int> counter(size);
1.311 for (int i = 0; i < size; ++i) {
1.312 - counter[i] = 0;
1.313 + counter[i] = 0;
1.314 }
1.315 Key *it = first;
1.316 while (first != last) {
1.317 - counter[valueByte(functor(*first), byte)]++;
1.318 - ++first;
1.319 + counter[valueByte(functor(*first), byte)]++;
1.320 + ++first;
1.321 }
1.322 int prev, num = 0;
1.323 for (int i = size / 2; i < size; ++i) {
1.324 - prev = num;
1.325 - num += counter[i];
1.326 - counter[i] = prev;
1.327 + prev = num;
1.328 + num += counter[i];
1.329 + counter[i] = prev;
1.330 }
1.331 for (int i = 0; i < size / 2; ++i) {
1.332 - prev = num;
1.333 - num += counter[i];
1.334 - counter[i] = prev;
1.335 + prev = num;
1.336 + num += counter[i];
1.337 + counter[i] = prev;
1.338 }
1.339 while (it != last) {
1.340 - target[counter[valueByte(functor(*it), byte)]++] = *it;
1.341 - ++it;
1.342 + target[counter[valueByte(functor(*it), byte)]++] = *it;
1.343 + ++it;
1.344 }
1.345 }
1.346
1.347 -
1.348 +
1.349 template <typename Value, typename Iterator, typename Functor>
1.350 void counterSignedSort(Iterator first, Iterator last, Functor functor) {
1.351 if (first == last) return;
1.352 @@ -328,30 +331,30 @@
1.353 int length = std::distance(first, last);
1.354 Key* buffer = allocator.allocate(2 * length);
1.355 try {
1.356 - bool dir = true;
1.357 - std::copy(first, last, buffer);
1.358 - for (int i = 0; i < int(sizeof(Value)) - 1; ++i) {
1.359 - if (dir) {
1.360 - counterIntroSort(buffer, buffer + length, buffer + length,
1.361 - i, functor);
1.362 - } else {
1.363 - counterIntroSort(buffer + length, buffer + 2 * length, buffer,
1.364 - i, functor);
1.365 - }
1.366 - dir = !dir;
1.367 - }
1.368 - if (dir) {
1.369 - signedCounterIntroSort(buffer, buffer + length, buffer + length,
1.370 - sizeof(Value) - 1, functor);
1.371 - std::copy(buffer + length, buffer + 2 * length, first);
1.372 - } else {
1.373 - signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer,
1.374 - sizeof(Value) - 1, functor);
1.375 - std::copy(buffer, buffer + length, first);
1.376 - }
1.377 + bool dir = true;
1.378 + std::copy(first, last, buffer);
1.379 + for (int i = 0; i < int(sizeof(Value)) - 1; ++i) {
1.380 + if (dir) {
1.381 + counterIntroSort(buffer, buffer + length, buffer + length,
1.382 + i, functor);
1.383 + } else {
1.384 + counterIntroSort(buffer + length, buffer + 2 * length, buffer,
1.385 + i, functor);
1.386 + }
1.387 + dir = !dir;
1.388 + }
1.389 + if (dir) {
1.390 + signedCounterIntroSort(buffer, buffer + length, buffer + length,
1.391 + sizeof(Value) - 1, functor);
1.392 + std::copy(buffer + length, buffer + 2 * length, first);
1.393 + } else {
1.394 + signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer,
1.395 + sizeof(Value) - 1, functor);
1.396 + std::copy(buffer, buffer + length, first);
1.397 + }
1.398 } catch (...) {
1.399 - allocator.deallocate(buffer, 2 * length);
1.400 - throw;
1.401 + allocator.deallocate(buffer, 2 * length);
1.402 + throw;
1.403 }
1.404 allocator.deallocate(buffer, 2 * length);
1.405 }
1.406 @@ -366,38 +369,38 @@
1.407 int length = std::distance(first, last);
1.408 Key *buffer = allocator.allocate(2 * length);
1.409 try {
1.410 - bool dir = true;
1.411 - std::copy(first, last, buffer);
1.412 - for (int i = 0; i < int(sizeof(Value)); ++i) {
1.413 - if (dir) {
1.414 - counterIntroSort(buffer, buffer + length,
1.415 - buffer + length, i, functor);
1.416 - } else {
1.417 - counterIntroSort(buffer + length, buffer + 2 * length,
1.418 - buffer, i, functor);
1.419 - }
1.420 - dir = !dir;
1.421 - }
1.422 - if (dir) {
1.423 - std::copy(buffer, buffer + length, first);
1.424 - } else {
1.425 - std::copy(buffer + length, buffer + 2 * length, first);
1.426 - }
1.427 + bool dir = true;
1.428 + std::copy(first, last, buffer);
1.429 + for (int i = 0; i < int(sizeof(Value)); ++i) {
1.430 + if (dir) {
1.431 + counterIntroSort(buffer, buffer + length,
1.432 + buffer + length, i, functor);
1.433 + } else {
1.434 + counterIntroSort(buffer + length, buffer + 2 * length,
1.435 + buffer, i, functor);
1.436 + }
1.437 + dir = !dir;
1.438 + }
1.439 + if (dir) {
1.440 + std::copy(buffer, buffer + length, first);
1.441 + } else {
1.442 + std::copy(buffer + length, buffer + 2 * length, first);
1.443 + }
1.444 } catch (...) {
1.445 - allocator.deallocate(buffer, 2 * length);
1.446 - throw;
1.447 + allocator.deallocate(buffer, 2 * length);
1.448 + throw;
1.449 }
1.450 allocator.deallocate(buffer, 2 * length);
1.451 }
1.452
1.453
1.454
1.455 - template <typename Value,
1.456 - bool sign = std::numeric_limits<Value>::is_signed >
1.457 + template <typename Value,
1.458 + bool sign = std::numeric_limits<Value>::is_signed >
1.459 struct CounterSortSelector {
1.460 template <typename Iterator, typename Functor>
1.461 static void sort(Iterator first, Iterator last, Functor functor) {
1.462 - counterSignedSort<Value>(first, last, functor);
1.463 + counterSignedSort<Value>(first, last, functor);
1.464 }
1.465 };
1.466
1.467 @@ -405,7 +408,7 @@
1.468 struct CounterSortSelector<Value, false> {
1.469 template <typename Iterator, typename Functor>
1.470 static void sort(Iterator first, Iterator last, Functor functor) {
1.471 - counterUnsignedSort<Value>(first, last, functor);
1.472 + counterUnsignedSort<Value>(first, last, functor);
1.473 }
1.474 };
1.475
1.476 @@ -413,34 +416,33 @@
1.477
1.478 /// \ingroup auxalg
1.479 ///
1.480 - /// \brief Sorts stable the STL compatible range into ascending order.
1.481 + /// \brief Sorts the STL compatible range into ascending order in a stable
1.482 + /// way.
1.483 ///
1.484 - /// The \c counterSort sorts the STL compatible range into ascending
1.485 - /// order. The counter sort algorithm can sort the items which
1.486 - /// mapped to an integer with an adaptable unary function \c functor
1.487 - /// and the order will be ascending by these mapped values. As
1.488 - /// function specialization it is possible to use a normal function
1.489 - /// instead of the functor object or if the functor is not given it
1.490 - /// will use an identity function instead.
1.491 + /// This function sorts an STL compatible range into ascending
1.492 + /// order according to an integer mapping in the same as radixSort() does.
1.493 ///
1.494 - /// The implemented counter sort use a radix forward sort on the
1.495 + /// This sorting algorithm is stable, i.e. the order of two equal
1.496 + /// element remains the same after the sorting.
1.497 + ///
1.498 + /// This sort algorithm use a radix forward sort on the
1.499 /// bytes of the integer number. The algorithm sorts the items
1.500 - /// byte-by-byte, first it counts how many times occurs a byte value
1.501 - /// in the containerm, and with the occurence number the container
1.502 - /// can be copied to an other in asceding order in \c O(n) time.
1.503 - /// Let be \c c the maximal capacity of the integer type and \c n
1.504 - /// the number of the items in the container, the time complexity of
1.505 - /// the algorithm is \f$ O(\log(c)n) \f$ and the additional space
1.506 - /// complexity is \f$ O(n) \f$.
1.507 + /// byte-by-byte. First, it counts how many times a byte value occurs
1.508 + /// in the container, then it copies the corresponding items to
1.509 + /// another container in asceding order in \c O(n) time.
1.510 ///
1.511 - /// The sorting algorithm is stable, i.e. the order of two equal
1.512 - /// element remains the same.
1.513 + /// The time complexity of the algorithm is \f$ O(\log(c)n) \f$ and
1.514 + /// it uses \f$ O(n) \f$, additional space, where \c c is the
1.515 + /// maximal value and \c n is the number of the items in the
1.516 + /// container.
1.517 ///
1.518 +
1.519 /// \param first The begin of the given range.
1.520 /// \param last The end of the given range.
1.521 /// \param functor An adaptible unary function or a normal function
1.522 /// which maps the items to any integer type which can be either
1.523 /// signed or unsigned.
1.524 + /// \sa radixSort()
1.525 template <typename Iterator, typename Functor>
1.526 void counterSort(Iterator first, Iterator last, Functor functor) {
1.527 using namespace _radix_sort_bits;