BucketSort.cpp

//  
//  algorithm - some algorithms in "Introduction to Algorithms", third edition
//  Copyright (C) 2018  lxylxy123456
//  
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Affero General Public License as
//  published by the Free Software Foundation, either version 3 of the
//  License, or (at your option) any later version.
//  
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Affero General Public License for more details.
//  
//  You should have received a copy of the GNU Affero General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
//  

#ifndef MAIN
#define MAIN
#define MAIN_BucketSort
#endif

#ifndef FUNC_BucketSort
#define FUNC_BucketSort

#include <cassert>
#include "utils.h"
#include "InsertSort.cpp"

template <typename T>
void BucketSort(std::vector<T>& A, T a_min, T a_max) {
	const size_t n = A.size(); 
	const T a_diff = a_max - a_min; 
	// for all i, a_min <= A[i] < a_max
	std::vector<std::vector<T>> B; 
	B.resize(n); 
	for (typename std::vector<T>::iterator i = A.begin(); i != A.end(); i++)
		B[(*i - a_min) * n / a_diff].push_back(*i); 
	typename std::vector<T>::iterator b = A.begin(); 
	for (typename std::vector<std::vector<T>>::iterator i = B.begin(); 
		i != B.end(); i++) {
		InsertSort(*i); 
		b = std::copy(i->begin(), i->end(), b); 
	}
	assert(b == A.end()); 
}
#endif

#ifdef MAIN_BucketSort
int main(int argc, char *argv[]) {
	std::vector<int> a; 
	const size_t n = get_argv(argc, argv, 1, 10); 
	const size_t compute = get_argv(argc, argv, 2, 3); 
	random_integers(a, 0, n - 1, n); 
	std::vector<int> b(a); 
	if (compute >> 0 & 1) {
		InsertSort(a); 
		output_integers(a); 
	}
	if (compute >> 1 & 1) {
		BucketSort<int>(b, 0, n); 
		output_integers(b); 
		if (compute >> 0 & 1)
			std::cout << std::boolalpha << (a == b) << std::endl; 
	}
	return 0; 
}
#endif