Quick Sort 25 XP Medium

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Quick Sort picks a pivot, partitions the array so all smaller elements go left and larger go right, then recursively sorts both sides.

# Pivot = 4: [3, 6, 8, 2, 4, 1]
# Partition: [3, 2, 1] [4] [6, 8]
# Recursively sort left and right
# Result: [1, 2, 3, 4, 6, 8]

Time: O(n log n) average, O(n²) worst (rare with good pivot). Space: O(log n) for recursion stack. In practice, it's often the fastest sorting algorithm.

Pivot strategies: last element, first element, random, or median-of-three.

📋 Instructions

Implement a simple `quick_sort(arr)` using the last element as pivot. Sort `[10, 7, 8, 9, 1, 5]` and print the result.

Choose last element as pivot. Partition: use pointer i starting before the subarray. For each element < pivot, increment i and swap. Finally swap pivot to position i+1. Recursively sort left and right of pivot.

🧪 Test Cases

Input

quick_sort([10, 7, 8, 9, 1, 5])

Expected

[1, 5, 7, 8, 9, 10]

Test case 1

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main.py

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Output

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