103-merge_sort.c

#include "sort.h"

/**
 * merge_sort - Function that sorts an array w/ merge sort algorithm
 * @array: The array of integers
 * @size: The array size
 *
 * Return: None
 */
void merge_sort(int *array, size_t size)
{
	int *buffer;

	if (array == NULL || size < 2)
		return;

	buffer = malloc(sizeof(int) * size);
	if (buffer == NULL)
		return;

	top_down_merge_sort(array, buffer, 0, size);
	free(buffer);
}

/**
 * top_down_merge_sort - Function to sort buffer with recursion
 * @array: The array of integers
 * @buffer: The copy of the array of integers
 * @top: Top index of the array
 * @down: Down index of the array
 *
 * Return: None
 */
void top_down_merge_sort(int *array, int *buffer, size_t top, size_t down)
{
	size_t i, j, k, mid;

	if (down - top > 1)
	{
		mid = top + (down - top) / 2;
		top_down_merge_sort(array, buffer, top, mid);
		top_down_merge_sort(array, buffer, mid, down);
		printf("Merging...\n[left]: ");
		for (i = top; i < mid; i++)
		{
			printf("%d", array[i]);
			if (i != mid - 1)
				printf(", ");
		}
		printf("\n[right]: ");
		for (i = mid; i < down; i++)
		{
			printf("%d", array[i]);
			if (i != down - 1)
				printf(", ");
		}
		printf("\n");
		for (i = top, j = mid, k = 0; k < (down - top); k++)
		{
			if (i < mid && (j >= down || array[i] <= array[j]))
				buffer[k] = array[i], i++;
			else
				buffer[k] = array[j], j++;
		}
		printf("[Done]: ");
		for (i = top; i < down; i++)
		{
			array[i] = buffer[i - top];
			printf("%d", array[i]);
			if (i != down - 1)
				printf(", ");
		}
		printf("\n");
	}
}