Stress test

stressTest.py

import time
import random

'''Course: https://www.coursera.org/learn/algorithmic-toolbox#about'''


def maxPairwiseProductSlow(numberList):
    '''prints max product between any two numbers in the numberList
    slow approach'''

    result = 0
    lenOfNumList = len(numberList)

    for i in range(lenOfNumList):
        for j in range(lenOfNumList):
            if numberList[i] * numberList[j] > result:
                result = numberList[i] * numberList[j]

    return result




def maxPairwiseProductFast(numberList):
    '''prints max product between any two numbers in the numberList
    fast approach'''

    lenOfNumList = len(numberList)

    maxIndex1 = -1
    for i in range(lenOfNumList):
        if (maxIndex1 == -1) or (numberList[i] > numberList[maxIndex1]):
            maxIndex1 = i


    maxIndex2 = -1
    for j in range(lenOfNumList):
        if (maxIndex1 != maxIndex2) and (maxIndex2 == -1 or numberList[j] > numberList[maxIndex2]):
            maxIndex2 = j

    return numberList[maxIndex1] * numberList[maxIndex2]






def stressTestMaxPairwiseProductFunctions(minLenOfList, maxLenOfList, minRandomNumber, maxRandomNumber, maxSeconds):
    '''compares the results of two functions (maxPairwiseProductSlow, maxPairwiseProductFast) for same input
    which is randomly generated. If the results are wrong, it stops. Otherwise, it will stop after maxSeconds'''

    startTime = time.time()
    endTime = time.time() - startTime

    while (endTime <= maxSeconds):

        lenOfNumList = random.randrange(minLenOfList, maxLenOfList)
        print("length of list: ", lenOfNumList)

        numberList = []
        for i in range(lenOfNumList):
            numberList.append(random.randrange(minRandomNumber, maxRandomNumber))
        print("sequence of random numbers: ", numberList)


        result1 = maxPairwiseProductSlow(numberList=numberList)
        result2 = maxPairwiseProductFast(numberList=numberList)

        if result1 != result2:
            print("Wrong answer found: ", result1, " ", result2)
            break
        else:
            print("OK")


        endTime = time.time() - startTime

    print("\nThere was no wrong answer found in "+str(maxSeconds)+" seconds\n")



if __name__ == '__main__':

    stressTestMaxPairwiseProductFunctions(minLenOfList=2, maxLenOfList=11, minRandomNumber=0, maxRandomNumber=99999, maxSeconds=10)