77 lines
2 KiB
C
77 lines
2 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* ft_radixsort.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: thrieg <thrieg@student.42mulhouse.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2024/11/18 14:18:55 by alier #+# #+# */
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/* Updated: 2025/02/16 19:06:42 by thrieg ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include <stdlib.h>
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#include <stdbool.h>
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#include "ft_sorting.h"
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static void ft_naive_countsort2(struct s_countsort cs)
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{
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size_t i;
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i = cs.size - 1;
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while (true)
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{
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cs.tmp[cs.count[(cs.a[i] / cs.exp) % 10] - 1] = cs.a[i];
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cs.count[(cs.a[i] / cs.exp) % 10]--;
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if (i == 0)
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break ;
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i--;
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}
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ft_memcpy(cs.a, cs.tmp, cs.size * sizeof(*cs.a));
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}
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/*
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* used by `ft_naive_radixsort`
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*/
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static void ft_naive_countsort(size_t size, unsigned int a[size],
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unsigned int exp)
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{
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unsigned int *tmp;
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unsigned int count[10];
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size_t i;
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tmp = malloc(size * sizeof(unsigned int));
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ft_bzero(count, 10 * sizeof(unsigned int));
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i = 0;
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while (i < size)
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{
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count[(a[i] / exp) % 10]++;
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i++;
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}
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i = 1;
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while (i < 10)
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{
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count[i] += count[i - 1];
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i++;
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}
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ft_naive_countsort2((struct s_countsort){size, a, exp, tmp, count});
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free(tmp);
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}
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/*
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* Worst-case performance: O(size * max_digits)
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* Worst-case space complexity: O(size + max_digits)
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*/
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void ft_naive_radixsort(size_t size, unsigned int a[size])
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{
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unsigned int m;
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unsigned int exp;
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m = ft_max_uint(size, a);
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exp = 1;
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while (m / exp > 0)
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{
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ft_naive_countsort(size, a, exp);
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exp *= 10;
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}
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}
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