Majority Element Moore's Voting Algorithm in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the candidate for majority element.

DSA Python

candidate = [1]
count = 0

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

ANone

B0

C1

Darr[0]

Attempts:

3 left

💡 Hint

Common Mistakes

Setting candidate to an element before starting the loop.

Using a number like 0 or 1 which may not be in the array.

We start with no candidate, so candidate is set to None.

2fill in blank

medium

Complete the code to update the candidate when count is zero.

DSA Python

if count == 0:
    candidate = [1]

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

Ai

Barr[i]

CNone

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning candidate to the index instead of the element.

Assigning candidate to None or count.

When count is zero, we pick the current element as the new candidate.

3fill in blank

hard

Fix the error in updating count based on the current element.

DSA Python

if arr[i] == candidate:
    count [1] 1
else:
    count -= 1

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

A-=

B=

C*=

D+=

Attempts:

3 left

💡 Hint

Common Mistakes

Decreasing count when elements match.

Assigning count instead of incrementing.

When the current element matches the candidate, we increase count by 1.

4fill in blank

hard

Fill both blanks to complete the verification step for majority element.

DSA Python

count = 0
for num in arr:
    if num [1] candidate:
        count [2] 1

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

A==

B+=

C!=

D-=

Attempts:

3 left

💡 Hint

Common Mistakes

Using != instead of == in the condition.

Decreasing count instead of increasing.

We count how many times the candidate appears by checking equality and incrementing count.

5fill in blank

hard

Fill all three blanks to return the majority element or -1 if none exists.

DSA Python

if count [1] len(arr) // 2:
    return [2]
else:
    return [3]

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

A>

Bcandidate

C-1

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > for majority check.

Returning count instead of candidate.

Returning 0 instead of -1 when no majority.

If candidate count is more than half the array length, return candidate; otherwise, return -1.