ch04-02.md

4.2 Quicksort

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  • 퀵정렬

• 👉 Read "Grokking Algorithms"

• 🍑 퀵정렬 증명

• 🐍 python practice

# quicksort

def quicksort(array):
    if len(array) < 2:
        return array
    else:
        pivot = array[0]  # the first item as a pivot
        less, greater = [], []
        for item in array[1:]:
            if item <= pivot:
                less.append(item)
            else:
                greater.append(item)
        return quicksort(less) + [pivot] + quicksort(greater)

# test quicksort
my_array = [10, 5, 2, 3]
print(quicksort(my_array))

• 🐍 python practice

# quicksort (using Python List Comprehension)

def quicksort(array):
    if len(array) < 2:
        return array
    else:
        pivot = array[0]  # the first item as a pivot
        less = [item for item in array[1:] if item <= pivot]    # List Comprehension
        greater = [item for item in array[1:] if item > pivot]
        return quicksort(less) + [pivot] + quicksort(greater)

# test quicksort
my_array = [10, 5, 2, 3]
print(quicksort(my_array))