DSA Bonus Questions

[asifmohammed1]

Question 1: Find the Second Largest Element

Given an array of integers, find the second largest element.

Input

arr = [10, 20, 5, 8, 25]

Output

20

Example

Largest = 25
Second Largest = 20

Concepts

• Arrays/Lists
• Loops
• Conditions

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Question 2: Count Frequency of Elements

Given an array, count how many times each element appears.

Input

arr = [1, 2, 2, 3, 1, 2, 4]

Output

{
    1: 2,
    2: 3,
    3: 1,
    4: 1
}

Concepts

• Dictionary
• Loops

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Question 3: Check Palindrome Number

Given a number, check whether it is a palindrome.

Input

121

Output

Palindrome

Input

123

Output

Not Palindrome

Concepts

• Loops
• Modulus (%)
• Integer Operations

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Question 4: Find Missing Number

An array contains numbers from 1 to n with one number missing.

Find the missing number.

Input

arr = [1, 2, 3, 5]

Output

4

Hint

Expected numbers:

1 2 3 4 5

Actual numbers:

1 2 3 5

Missing:

4

Concepts

• Arrays
• Sum Formula
• Loops

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Interview Bonus

Reverse an Array

Input

[1, 2, 3, 4, 5]

Output

[5, 4, 3, 2, 1]

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Find Maximum Element

Input

[10, 50, 20, 80, 30]

Output

80

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Count Even and Odd Numbers

Input

[1, 2, 3, 4, 5, 6]

Output

Even = 3
Odd = 3

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Sum of Digits

Input

1234

Output

10