Versions

Quicksort.c → Quicksort.v1.c

@@ -19,9 +19,9 @@ int partition (int arr[], int low, int high) {
    return (i + 1);
 }
 
-void quickSort(int arr[], int low, int high){
+void quickSort(int arr[], long int low, long int high){
    if (low < high){
-      int pi = partition(arr, low, high);
+      long int pi = partition(arr, low, high);
       quickSort(arr, low, pi - 1);
       quickSort(arr, pi + 1, high);
    }
@@ -37,7 +37,9 @@ void printArray(int arr[], int size){
 int main(){
    int arr[] = {10, 8, 11, 15, 7, 12, 33, 3};
    int n = sizeof(arr)/sizeof(arr[0]);
+
    quickSort(arr, 0, n-1);
+
    printf("The sorted array is: \n");
    printArray(arr, n);
    return 0;

Quicksort.v2.c

@@ -0,0 +1,51 @@
+#include<stdio.h>
+
+void swap(int* a, int* b) {
+   int t = *a;
+   *a = *b;
+   *b = t;
+}
+
+int partition (int arr[], int low, int high) {
+   int pivot = arr[high];
+   int i = (low - 1);
+   for (int j = low; j <= high- 1; j++){
+      if (arr[j] <= pivot){
+         i++;
+         swap(&arr[i], &arr[j]);
+      }
+   }
+   swap(&arr[i + 1], &arr[high]);
+   return (i + 1);
+}
+
+void quickSort(int arr[], long int low, long int high){
+   if (low < high){
+      long int pi = partition(arr, low, high);
+      quickSort(arr, low, pi - 1);
+      quickSort(arr, pi + 1, high);
+   }
+}
+
+void printArray(int arr[], int size){
+   int i;
+   for (i=0; i < size; i++)
+      printf("%d ", arr[i]);
+   printf("\n");
+}
+
+int main(){
+   long int n = 10000;
+   int *arr = (int*)malloc(n * sizeof(int));
+   srand(0);
+   long int i;
+   for (i = 0; i < n; i++) {
+      arr[i] = rand() % n;
+   }
+
+   quickSort(arr, 0, n-1);
+
+   printf("The sorted array is: \n");
+   printArray(arr, n);
+   return 0;
+}

Quicksort.v3.c

@@ -0,0 +1,63 @@
+#include<stdio.h>
+#include <time.h>
+
+void swap(int* a, int* b) {
+   int t = *a;
+   *a = *b;
+   *b = t;
+}
+
+int partition (int arr[], int low, int high) {
+   int pivot = arr[high];
+   int i = (low - 1);
+   for (int j = low; j <= high- 1; j++){
+      if (arr[j] <= pivot){
+         i++;
+         swap(&arr[i], &arr[j]);
+      }
+   }
+   swap(&arr[i + 1], &arr[high]);
+   return (i + 1);
+}
+
+void quickSort(int arr[], long int low, long int high){
+   if (low < high){
+      long int pi = partition(arr, low, high);
+      quickSort(arr, low, pi - 1);
+      quickSort(arr, pi + 1, high);
+   }
+}
+
+void printArray(int arr[], int size){
+   int i;
+   for (i=0; i < size; i++)
+      printf("%d ", arr[i]);
+   printf("\n");
+}
+
+int main(){
+
+   long int n = 100000000;
+   int *arr = (int*)malloc(n * sizeof(int));
+   srand(0);
+   long int i;
+   for (i = 0; i < n; i++) {
+      arr[i] = rand() % n;
+   }
+
+
+   clock_t start, end;
+   double cpu_time_used;
+
+   start = clock();
+   quickSort(arr, 0, n-1);
+   end = clock();
+
+   cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
+
+   printf("CLOCKS_PER_SEC: %ld \n", CLOCKS_PER_SEC);
+   printf("CPU time used is: %f \n", cpu_time_used);
+
+
+   return 0;
+}