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Write a program to compute the quicksort for the given input array
Answer:
Asked In ::
Language:
Rahul Jain
15 Jun, 2017 10:31 AM
<!DOCTYPE html>
<html>
<body>
<?php
$unsorted = array(43,21,2,1,9,24,2,99,23,8,7,114,92,5);
function quick_sort($array)
{
// find array size
$length = count($array);
// base case test, if array of length 0 then just return array to caller
if($length <= 1){
return $array;
}
else{
// select an item to act as our pivot point, since list is unsorted first position is easiest
$pivot = $array[0];
// declare our two arrays to act as partitions
$left = $right = array();
// loop and compare each item in the array to the pivot value, place item in appropriate partition
for($i = 1; $i < count($array); $i++)
{
if($array[$i] < $pivot){
$left[] = $array[$i];
}
else{
$right[] = $array[$i];
}
}
// use recursion to now sort the left and right lists
return array_merge(quick_sort($left), array($pivot), quick_sort($right));
}
}
$sorted = quick_sort($unsorted);
print_r($sorted);
?>
</body>
</html>
Language:
Aswin
7 Jul, 2017 9:30 AM
#include<stdio.h>
// A utility function to swap two elements
void swap(int* a, int* b)
{
int t = *a;
*a = *b;
*b = t;
}
/* This function takes last element as pivot, places
the pivot element at its correct position in sorted
array, and places all smaller (smaller than pivot)
to left of pivot and all greater elements to right
of pivot */
int partition (int arr[], int low, int high)
{
int pivot = arr[high]; // pivot
int i = (low - 1); // Index of smaller element
for (int j = low; j <= high- 1; j++)
{
// If current element is smaller than or
// equal to pivot
if (arr[j] <= pivot)
{
i++; // increment index of smaller element
swap(&arr[i], &arr[j]);
}
}
swap(&arr[i + 1], &arr[high]);
return (i + 1);
}
/* The main function that implements QuickSort
arr[] --> Array to be sorted,
low --> Starting index,
high --> Ending index */
void quickSort(int arr[], int low, int high)
{
if (low < high)
{
/* pi is partitioning index, arr[p] is now
at right place */
int pi = partition(arr, low, high);
// Separately sort elements before
// partition and after partition
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
}
}
/* Function to print an array */
void printArray(int arr[], int size)
{
int i;
for (i=0; i < size; i++)
printf("%d ", arr[i]);
printf("n");
}
// Driver program to test above functions
int main()
{
int arr[] = {10, 7, 8, 9, 1, 5};
int n = sizeof(arr)/sizeof(arr[0]);
quickSort(arr, 0, n-1);
printf("Sorted array: n");
printArray(arr, n);
return 0;
}
Language:
Neel
7 Jul, 2017 9:30 AM
#include <iostream>
using namespace std;
void quick_sort(int[],int,int);
int partition(int[],int,int);
int main()
{
int a[50],n,i;
cout<<"How many elements?";
cin>>n;
cout<<"\nEnter array elements:";
for(i=0;i<n;i++)
cin>>a[i];
quick_sort(a,0,n-1);
cout<<"\nArray after sorting:";
for(i=0;i<n;i++)
cout<<a[i]<<" ";
return 0;
}
void quick_sort(int a[],int l,int u)
{
int j;
if(l<u)
{
j=partition(a,l,u);
quick_sort(a,l,j-1);
quick_sort(a,j+1,u);
}
}
int partition(int a[],int l,int u)
{
int v,i,j,temp;
v=a[l];
i=l;
j=u+1;
do
{
do
i++;
while(a[i]<v&&i<=u);
do
j--;
while(v<a[j]);
if(i<j)
{
temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}while(i<j);
a[l]=a[j];
a[j]=v;
return(j);
}
