add: quick sort split array

README.md

@@ -44,6 +44,7 @@ GCCを使用してコンパイルしています。
 
 - 2022/04/22 q_sort
 - 2022/04/26 quick_sort
+- 2022/04/28 array_quick_sort
 
 #### 処理内容
 

quick_sort/array_quick_sort.c

@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int
+array_copy(
+    int *array1,
+    int *array2,
+    int array2_size
+)
+{
+    int i;
+
+    for ( i = 0 ; i < array2_size ; i++ ) {
+        array1[i] = array2[i];
+    }
+
+    return 0;
+}
+
+int
+quick_sort(
+    int *array,
+    int left,
+    int right
+)
+{
+    int *group_small;
+    int *group_large;
+    int small_index = 0;
+    int small_size  = 0;
+    int large_index = 0;
+    int large_size  = 0;
+
+    int i   = 0;
+    int range   = right - left;
+    int pivot;
+    int pivot_index = 0;
+
+    if ( left >= right ) {
+        return -1;
+    }
+
+    group_small = (int *)malloc(sizeof(int) * range);
+    if ( group_small == NULL ) {
+        return -1;
+    }
+
+    group_large = (int *)malloc(sizeof(int) * range);
+    if ( group_large == NULL ) {
+        free(group_small);
+        return -1;
+    }
+
+    pivot = array[left];
+
+    for ( i = left + 1 ; i <= right ; i++ ) {
+        if ( array[i] < pivot ) {
+            group_small[small_index] = array[i];
+            small_index++;
+            small_size++;
+        } else {
+            group_large[large_index] = array[i];
+            large_index++;
+            large_size++;
+        }
+    }
+
+    pivot_index = left + small_size;
+
+    array_copy(array + left, group_small, small_size);
+    array[pivot_index] = pivot;
+    array_copy(array + pivot_index + 1, group_large, large_size);
+
+    free(group_small);
+    free(group_large);
+
+    quick_sort(array, left, pivot_index - 1);
+    quick_sort(array, pivot_index + 1, right);
+
+    return 0;
+}
+
+int
+main(
+    int argc,
+    char *argv[]
+)
+{
+    int i;
+
+    int length = 200;
+    int rand_limit = 100;
+
+    if ( argc > 1 ) {
+        length = atoi(argv[1]);
+    }
+
+    int array[length];
+
+    srand((int)time(NULL));
+
+    for ( i = 0 ; i < length ; i++ ) {
+        array[i] = rand() % rand_limit + 1;
+    }
+
+    time_t start_at = time(NULL);
+    quick_sort(array, 0, length - 1);
+    time_t end_at = time(NULL);
+
+    for ( i = 0 ; i < length ; i++ ) {
+        printf("%d\n", array[i]);
+    }
+
+    printf("elapsed: %lds\n", end_at - start_at);
+
+    return 0;
+}