feat: implement merge sort algorithm with array of ints

Author: chee-zaram

103-O

@@ -0,0 +1,3 @@
+O(nlog(n))
+O(nlog(n))
+O(nlog(n))

103-merge_sort.c

@@ -0,0 +1,89 @@
+#include "sort.h"
+#include <stdlib.h>
+
+/**
+ * merge_sort - Implements the merge sort algorithm using an array of ints
+ * @array: Array of ints
+ * @size: Length of the array
+ */
+void merge_sort(int *array, size_t size)
+{
+	int *temp_array = NULL;
+
+	if (!array || size < 2)
+		return;
+
+	temp_array = malloc(sizeof(int) * size);
+	if (!temp_array)
+		return;
+
+	copy_array(array, temp_array, size);
+	split(temp_array, 0, size, array);
+	free(temp_array);
+}
+
+/**
+ * copy_array - Copies the integers in @array of size @size to @temp_array
+ * @array: Source array
+ * @temp_array: Destination array
+ * @size: Length of @array
+ */
+void copy_array(int *array, int *temp_array, size_t size)
+{
+	size_t idx;
+
+	for (idx = 0; idx < size; idx++)
+		temp_array[idx] = array[idx];
+}
+
+/**
+ * split - Divides an array into two until each array has one integer only
+ * @temp_array: Temporary array for working on the sort
+ * @beg: Beginning index in the array
+ * @end: Ending index in the array
+ * @array: Main array
+ */
+void split(int *temp_array, size_t beg, size_t end, int *array)
+{
+	size_t mid = 0;
+
+	if (end - beg < 2)
+		return;
+
+	mid = (end + beg) / 2;
+
+	split(array, beg, mid, temp_array);
+	split(array, mid, end, temp_array);
+
+	merge(temp_array, beg, mid, end, array);
+}
+
+/**
+ * merge - Merges integers in two array in a sorted order
+ * @array: Second array
+ * @beg: Start index in the array
+ * @mid: Middle index in the array
+ * @end: End index in the array
+ * @temp_array: First array
+ */
+void merge(int *array, size_t beg, size_t mid, size_t end, int *temp_array)
+{
+	size_t i = beg, j = mid, k;
+
+	printf("Merging...\n");
+	printf("[left]: ");
+	print_array(array + beg, mid - beg);
+	printf("[right]: ");
+	print_array(array + mid, end - mid);
+
+	for (k = beg; k < end; k++)
+	{
+		if (i < mid && (j >= end || array[i] <= array[j]))
+			temp_array[k] = array[i], i++;
+		else
+			temp_array[k] = array[j], j++;
+	}
+
+	printf("[Done]: ");
+	print_array(temp_array + beg, end - beg);
+}

sort.h

@@ -100,6 +100,11 @@ void counting_sort(int *array, size_t size);
 int find_max(int *array, size_t size);
 void sort(int *array, int *count, int *sorted_array, size_t size);
 
+void merge_sort(int *array, size_t size);
+void copy_array(int *array, int *temp_array, size_t size);
+void split(int *temp_array, size_t beg, size_t end, int *array);
+void merge(int *array, size_t beg, size_t mid, size_t end, int *temp_array);
+
 /* void sort_list_of_two_and_print(listint_t **list); */
 /* void sort_two_only(listint_t **list); */
 /* int sort_for_last_node(listint_t *node_to_insert); */