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Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

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This is a easy difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Meta.

What role is this question designed for?

This question is commonly asked for Machine Learning Engineer candidates at Meta during technical interviews.

Solve two linked list/array tasks | Meta Interview Question

Q: Solve two linked list/array tasks

This two-part question evaluates proficiency with fundamental data structures and algorithmic problem-solving—specifically linked list manipulation and array-based reasoning—within the Coding & Algorithms domain and emphasizes practical application skills in implementing efficient algorithms and analyzing time and space complexity.

You are given two independent coding tasks.

Task 1: Remove the N-th node from the end of a singly linked list

Given the head of a singly linked list and an integer n, remove the n-th node from the end of the list and return the head of the modified list.

Input

head : head node of a singly linked list (node has fields val and next )
n : integer

Output

The head of the list after removal

Constraints (typical interview assumptions)

1 <= n <= length(list)
List length can be up to 10^5

Example

List: 1 -> 2 -> 3 -> 4 -> 5 , n = 2
Result: 1 -> 2 -> 3 -> 5

Task 2: Find the k-th missing positive number from a strictly increasing array

You are given a strictly increasing array arr of positive integers and an integer k. Consider the infinite sequence of positive integers 1, 2, 3, .... Return the k-th positive integer that is missing from arr.

Input

arr : strictly increasing array of positive integers
k : positive integer

Output

The k-th missing positive number

Constraints (typical interview assumptions)

1 <= arr.length <= 10^5
1 <= arr[i] <= 10^9
1 <= k <= 10^9

Example

arr = [2, 3, 4, 7, 11] , k = 5
Missing positives are [1, 5, 6, 8, 9, 10, ...] → answer is 9

You are given two independent coding tasks.

Task 1: Remove the N-th node from the end of a singly linked list

Given the head of a singly linked list and an integer n, remove the n-th node from the end of the list and return the head of the modified list.

Input

head : head node of a singly linked list (node has fields val and next )
n : integer

Output

The head of the list after removal

Constraints (typical interview assumptions)

1 <= n <= length(list)
List length can be up to 10^5

Example

List: 1 -> 2 -> 3 -> 4 -> 5 , n = 2
Result: 1 -> 2 -> 3 -> 5

Task 2: Find the k-th missing positive number from a strictly increasing array

Input

arr : strictly increasing array of positive integers
k : positive integer

Output

The k-th missing positive number

Constraints (typical interview assumptions)

1 <= arr.length <= 10^5
1 <= arr[i] <= 10^9
1 <= k <= 10^9

Example

arr = [2, 3, 4, 7, 11] , k = 5
Missing positives are [1, 5, 6, 8, 9, 10, ...] → answer is 9

Solve two linked list/array tasks

Quick Overview

Task 1: Remove the N-th node from the end of a singly linked list

Task 2: Find the k-th missing positive number from a strictly increasing array

Submit Your Answer to Earn 20XP

Solve two linked list/array tasks

Quick Overview

Task 1: Remove the N-th node from the end of a singly linked list

Task 2: Find the k-th missing positive number from a strictly increasing array

Submit Your Answer to Earn 20XP