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Quick Sort

Certification: Intermediate Level Accuracy: 0% Submissions: 0 Points: 10

Write a JavaScript program to implement the Quick Sort algorithm to sort an array of integers in ascending order. Quick Sort is a divide-and-conquer algorithm that works by selecting a 'pivot' element from the array and partitioning the other elements into two sub-arrays according to whether they are less than or greater than the pivot.

Example 1
    
      
  • Input: arr = [64, 34, 25, 12, 22, 11, 90]
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  • Output: [11, 12, 22, 25, 34, 64, 90]
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  • Explanation: 
    • The initial array is [64, 34, 25, 12, 22, 11, 90]. 
    • Choose pivot (let's say 64), partition array around it. 
    • Recursively sort left partition [34, 25, 12, 22, 11] and right partition [90]. 
    • Continue partitioning and sorting until all elements are in correct order. 
    • Final sorted array is [11, 12, 22, 25, 34, 64, 90].
    •
Example 2
    
      
  • Input: arr = [5, 2, 8, 1, 9]
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  • Output: [1, 2, 5, 8, 9]
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  • Explanation: 
    • The initial array is [5, 2, 8, 1, 9]. 
    • Choose pivot (let's say 5), partition array into [2, 1] and [8, 9]. 
    • Recursively sort left partition [2, 1] to get [1, 2]. 
    • Recursively sort right partition [8, 9] which is already sorted. 
    • Combine results to get [1, 2, 5, 8, 9].
    •
Constraints
    
      
  • 1 ≤ arr.length ≤ 1000
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  • -1000 ≤ arr[i] ≤ 1000
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  • The array may contain duplicate elements
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  • Time Complexity: O(n log n) average case, O(n²) worst case
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  • Space Complexity: O(log n) due to recursion stack
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ArraysAlgorithmsTech MahindraSamsung
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Hint
Solution

Solution Hints

    
      
  • Choose a pivot element from the array (commonly the last element)
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  • Partition the array so elements smaller than pivot are on the left, larger on the right
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  • Recursively apply quicksort to the left and right subarrays
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  • Use two pointers technique for efficient partitioning
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  • Handle base case when array has 1 or 0 elements
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  • Swap elements during partitioning to maintain order
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Steps to solve by this approach:

 Step 1: Choose a pivot element from the array (typically the last element).
 Step 2: Partition the array by placing elements smaller than pivot to the left and larger to the right.
 Step 3: Use two pointers to efficiently rearrange elements during partitioning.
 Step 4: Recursively apply quicksort to the left subarray (elements before pivot).
 Step 5: Recursively apply quicksort to the right subarray (elements after pivot).
 Step 6: Handle base case when subarray has 1 or 0 elements (already sorted).
 Step 7: Continue until all subarrays are sorted and the entire array is sorted.

Submitted Code :