DSA · Theory

QuickSort on Singly Linked List

← All stacks

Theory

638/810

QuickSort on Singly Linked List

QuickSort on Singly Linked List is a DSA idea you prove with a ticket queue node, not with a slogan.

For QuickSort on Singly Linked List, Big-O is in play. Don’t blame it until you have traced a ticket queue node.

QuickSort on Singly Linked List exists so Farhan can keep a ticket queue node correct in a counter.

Use QuickSort on Singly Linked List when a ticket queue node must stay clear. If a simpler DSA step works, use that instead.

QuickSort on Singly Linked List miss — losing the next pointer on delete. Fix it before you talk about advanced DSA.

After QuickSort on Singly Linked List, Farhan should still remember losing the next pointer on delete.

One breath for QuickSort on Singly Linked List, then a ticket queue node, then losing the next pointer on delete. Sit down.

Diagram

  [10] → [20] → [30] → /
   head              tail

Exam tip

For QuickSort on Singly Linked List: definition + a counter + one failure.

Example

def quick_sort(arr):
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left = [x for x in arr if x < pivot]
    mid = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    return quick_sort(left) + mid + quick_sort(right)

print(quick_sort([5, 1, 4, 2, 3]))

QuickSort on Singly Linked List — quick sort partitions around a pivot, then sorts both sides.

Short notes

DefQuickSort on Singly Linked List — Farhan uses it for a ticket queue node in a counter.
RuleQuickSort on Singly Linked List → head → next → ….
RememberQuickSort on Singly Linked List + Big-O (a counter).
UseQuickSort on Singly Linked List in a counter (a ticket queue node).
TrapQuickSort on Singly Linked List — losing the next pointer on delete.
ExQuickSort on Singly Linked List → a ticket queue node.

def quick_sort(arr): if len(arr) <= 1: return arr pivot = arr[len(arr) // 2] left = [x for x in arr if x < pivot] mid = [x for x in arr if x == pivot] right = [x for x in arr if x > pivot] return quick_sort(left) + mid + quick_sort(right) print(quick_sort([5, 1, 4, 2, 3]))

QuickSort on Singly Linked List

Example

Short notes

Questions

QuickSort on Singly Linked List

Example

Short notes

Questions