Maximum Product Subarray in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the maximum product with the first element of the array.

DSA Python

def max_product_subarray(nums):
    max_prod = [1]
    return max_prod

Drag options to blanks, or click blank then click option'

Amax(nums)

B0

C1

Dnums[0]

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing max_prod to 0 or 1 which may be incorrect if the first element is negative or less than 1.

We start by setting max_prod to the first element because the maximum product subarray must include at least one element.

2fill in blank

medium

Complete the code to iterate through the array starting from the second element.

DSA Python

for i in [1](1, len(nums)):
    pass

Drag options to blanks, or click blank then click option'

Arange

Blist

Cenumerate

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using list or enumerate which do not directly generate index ranges.

Starting loop from 0 instead of 1.

We use range(1, len(nums)) to loop through the array starting from index 1.

3fill in blank

hard

Fix the error in updating the current maximum product by choosing the correct function to get the maximum.

DSA Python

curr_max = max(nums[i], curr_max * nums[i], [1] * nums[i])

Drag options to blanks, or click blank then click option'

Acurr_max

Bcurr_min

Cmax_prod

Dnums[i-1]

Attempts:

3 left

💡 Hint

Common Mistakes

Using curr_max instead of curr_min, missing cases where negative times negative is positive.

We use curr_min because multiplying a negative minimum product by a negative number can become a new maximum.

4fill in blank

hard

Fill both blanks to update current minimum product and maximum product so far.

DSA Python

curr_min = min(nums[i], [1] * nums[i], [2] * nums[i])
max_prod = max(max_prod, curr_max)

Drag options to blanks, or click blank then click option'

Acurr_min

Bcurr_max

Cmax_prod

Dnums[i]

Attempts:

3 left

💡 Hint

Common Mistakes

Using max_prod or nums[i] incorrectly in the min function.

Not updating max_prod after curr_max changes.

curr_min updates by considering nums[i], curr_min * nums[i], and curr_max * nums[i]. max_prod updates with the maximum found so far.

5fill in blank

hard

Fill all three blanks to swap current max and min when nums[i] is negative.

DSA Python

if nums[i] < 0:
    [1], [2] = [3], curr_max

Drag options to blanks, or click blank then click option'

Acurr_max

Bcurr_min

Attempts:

3 left

💡 Hint

Common Mistakes

Not swapping or swapping incorrectly causing wrong max/min tracking.

When nums[i] is negative, we swap curr_max and curr_min to correctly track max and min products.