78 lines
2.1 KiB
C++
78 lines
2.1 KiB
C++
/* Algorithms for OctaSTD.
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*
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* This file is part of OctaSTD. See COPYING.md for futher information.
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*/
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#ifndef OCTA_ALGORITHM_H
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#define OCTA_ALGORITHM_H
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#include "octa/functional.h"
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#include "octa/range.h"
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namespace octa {
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template<typename R, typename U>
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R partition(R range, U pred) {
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R ret = range;
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for (; !range.empty(); range.pop_first()) {
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if (pred(range.first())) {
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swap(range.first(), ret.first());
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ret.pop_first();
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}
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}
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return ret;
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}
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template<typename R, typename C>
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void insertion_sort(R range, C compare) {
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size_t rlen = range.length();
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for (size_t i = 1; i < rlen; ++i) {
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size_t j = i, v = range[i];
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while (j > 0 && !compare(range[j - 1], v)) {
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range[j] = range[j - 1];
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--j;
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}
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range[j] = v;
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}
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}
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template<typename R>
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void insertion_sort(R range) {
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insertion_sort(range, Less<typename RangeTraits<R>::value>());
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}
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namespace internal {
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template<typename T, typename U>
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struct UnaryCompare {
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T val;
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U comp;
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bool operator()(const T &v) const { return comp(v, val); }
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};
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template<typename R, typename C>
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void quicksort(R range, C compare) {
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if (range.length() <= 10) {
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insertion_sort(range, compare);
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return;
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}
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typename RangeTraits<R>::reference p = range[range.length() / 2];
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swap(p, range.last());
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R r = partition(range, UnaryCompare<decltype(p), C>{ p, compare });
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R l = range.slice(0, range.length() - r.length());
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swap(r.first(), r.last());
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quicksort(l, compare);
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quicksort(r, compare);
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}
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}
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template<typename R, typename C>
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void sort(R range, C compare) {
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internal::quicksort(range, compare);
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}
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template<typename R>
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void sort(R range) {
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sort(range, Less<typename RangeTraits<R>::value>());
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}
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}
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#endif |