Interview Prep

Practice Problems
← Back to Courses
TitleDifficultyTagsAction
Reverse String

Reverse a string in-place.

Beginner
#string
Open →
Valid Parentheses

Check if the input string is valid (open and close parentheses match).

Beginner
#stack
Open →
Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list.

Beginner
#linked-list
Open →
Remove Nth Node From End of List

Remove the nth node from the end of a linked list.

Intermediate
#linked-list
Open →
Valid Anagram

Check if two strings are anagrams of each other.

Beginner
#string#hashmap
Open →
Group Anagrams

Group anagrams from a list of strings.

Intermediate
#string#hashmap
Open →
Top K Frequent Elements

Find the k most frequent elements in the array.

Intermediate
#heap#hashmap
Open →
Product of Array Except Self

Return an array such that each element is the product of all elements except itself.

Advanced
#array
Open →
Longest Consecutive Sequence

Find the length of the longest consecutive elements sequence.

Advanced
#array#set
Open →
Min Stack

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

Intermediate
#stack#design
Open →
Binary Search

Implement binary search on a sorted array.

Beginner
#array#binary-search
Open →