Sorting Algorithms studies

sorting_studies.py

import sys
import time

#Deal with Python2 and Python3 inputs
def getInput(prompt):
    if (sys.version[0] == "2"):
        return raw_input(prompt)
    else:
        return input(prompt)

testInput = getInput("Input an array: ")

if type(testInput == str):
    testInput = [int(i) for i in testInput.strip("[]").split(",")]

# Insertion sort
def insertion(inputArray):
    for index, item in enumerate(inputArray):
        #start at 0 index
        if (index > 0):
            moveIndex = index-1
            while(item < inputArray[moveIndex] and moveIndex >= 0):
                temp = inputArray[moveIndex]
                inputArray[moveIndex] = item
                inputArray[moveIndex + 1] = temp
                moveIndex -= 1
    return inputArray

#testInputCopy = testInput
#print( insertion(testInputCopy) )

# Merge sort
# based off algorithm from here: http://geeksquiz.com/merge-sort/
def merge(inputArray, start, divide, end):
    j = 0 #index to follow in non-focused list
    k = start
    left = inputArray[start:divide]
    right = inputArray[divide:end]

    for index, item in enumerate(left):
        while j < len(right):
            if item > right[j]:
                inputArray[k] = right[j]
                j += 1
                k += 1
            else:
                break
        inputArray[k] = item
        k += 1

def mergeSort(inputArray, start, end):
    if start < end - 1:
        submax = int((start + end)/2)
        mergeSort(inputArray, start, submax)
        mergeSort(inputArray, submax, end)
        merge(inputArray, start, submax, end)
    else:
        return inputArray

returnCopy = testInput
print("before:")
print(returnCopy)
mergeSort(returnCopy, 0, len(testInput))
print("after:")
print( returnCopy )