117 lines
3.0 KiB
C++
117 lines
3.0 KiB
C++
/**
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This file is a part of rexy's general purpose library
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Copyright (C) 2020 rexy712
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef REXY_ALGORITHM_HPP
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#define REXY_ALGORITHM_HPP
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#include "utility.hpp" //swap
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#include "rexy.hpp"
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#include <cstdint> //SIZE_MAX
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#include <cstdlib> //size_t
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#include <type_traits>
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#include "detail/algorithm.hpp"
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namespace rexy{
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//Requires Iterators to be LegacyRandomAccessIterators
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//right is one past the end of the list
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template<class Iter, class Compare>
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constexpr void quicksort(Iter left, Iter right, const Compare& cmp)
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noexcept(noexcept(detail::qs_partition(left, right, cmp)))
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{
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while(left < right){
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auto real_right = right-1;
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auto pivot = detail::qs_partition(left, real_right, cmp);
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quicksort(left, pivot, cmp);
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left = ++pivot;
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}
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}
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//Requires Iterators to be LegacyRandomAccessIterators
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template<class HIter, class NIter>
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constexpr HIter two_way_search(const HIter& hstart, const HIter& hend, const NIter& nstart, const NIter& nend){
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size_t j = 0;
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size_t i = 0;
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size_t nlen = nend - nstart;
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size_t hlen = hend - hstart;
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auto [suffix, period] = detail::critical_factorization(nstart, nend);
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if(detail::iter_compare(nstart, nstart + period, suffix)){
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size_t memory = SIZE_MAX;
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while(j <= hlen - nlen){
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i = max(suffix, memory) + 1;
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//right side
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while(i < nlen && nstart[i] == hstart[i + j]){
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++i;
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}
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if(i >= nlen){
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i = suffix;
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//left side
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while(i > memory && nstart[i] == hstart[i + j]){
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--i;
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}
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if(i <= memory){
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return hstart + j;
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}
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j += period;
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memory = nlen - period - 1;
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}else{
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j += (i - suffix);
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memory = SIZE_MAX;
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}
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}
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}else{
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period = max(suffix + 1, nlen - suffix - 1) + 1;
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j = 0;
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while(j <= hlen - nlen){
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i = suffix + 1;
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//right side
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while(i < nlen && nstart[i] == hstart[i + j]){
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++i;
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}
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if(i >= nlen){
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i = suffix;
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//left side
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while(i != SIZE_MAX && nstart[i] == hstart[i + j]){
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--i;
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}
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if(i == SIZE_MAX){
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return hstart + j;
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}
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j += period;
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}else{
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j += (i - suffix);
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}
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}
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}
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return hend;
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}
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//searcher for use with generic search wrappers
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struct two_way_searcher{
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template<class HIter, class NIter>
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constexpr HIter operator()(const HIter& hstart, const HIter& hend, const NIter& nstart, const NIter& nend)const{
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return two_way_search(hstart, hend, nstart, nend);
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}
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};
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}
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#endif
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