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User interface coding
JavaScript functions
System design
Quiz
Algorithmic coding
Algorithmic Coding
Solve coding challenges involving performance-optimized data structures and algorithms.
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Number of questions
9
2
92
questions
Total time
4
8
48
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Questions List
Data Structures and Algorithms Interviews
Front end engineer's guide to DSA - important concepts to know, top practice questions to do and other tips
Guide
GUIDES
Selection Sort
Implement a function that performs a selection sort
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
3.08k done
Stack
Implement a stack data structure containing the common stack methods
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
8.99k done
Find Duplicates in Array
Implement a function to check if there are any duplicate numbers in the array
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
3.07k done
Find Missing Number in Sequence
Implement a function to find the missing element in a sorted array
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
2.57k done
Bubble Sort
Implement a function that performs a bubble sort
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
262 done
Count Set Bits in a Binary Number
Implement a function to find set bits in binary representation of a given integer
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
827 done
Insertion Sort
Implement a function that performs an insertion sort
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
4.11k done
Optimal Stock Trading
Implement a function to find the maximum profit achievable by buying and selling a stock once
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
1.03k done
Pair sum
Implement a function to find two numbers within an array of integers that add up to a target integer
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
1.15k done
String Anagram
Implement a function to determine if two strings are anagram of each other
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
1.04k done
Flip Binary Tree
Implement a function to flip the nodes in a binary tree
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
731 done
Binary Tree Maximum Depth
Implement a function to find the maximum depth of a binary tree
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
769 done
Staircase Climbing Combinations
Implement a function to find the number of ways to reach at the top of staircase
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
475 done
Balanced Brackets
Implement a function to determine if a string contains balanced brackets
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
2.23k done
Binary Tree Equal
Implement a function to determine whether two binary trees are equal
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
711 done
Bit Counting
Implement a function to find number of set bits from 0 to n
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
358 done
Bit Reversal
Implement a function to flip the order of the bits in a given number
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
284 done
Linked List Reversal
Implement a function to reverse a linked list
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
505 done
String Palindrome
Implement a function to determine if a string is a palindrome
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
707 done
Linked List Detect Cycle
Implement a function to detect if there are cycles in a linked list
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
451 done
Binary Tree Subtree
Implement a function to check if a binary tree is a subtree of another binary tree
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
412 done
Meeting Calendar
Implement a function to check if all meetings can be attended
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
535 done
Linked Lists Combine Two Sorted
Implement a function to combine two sorted linked list
Algorithmic coding
Algo coding
Difficulty
Easy
Languages
Users completed
385 done
Array Product Excluding Current
Implement a function to find the product of elements in an array excluding the current element
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.19k done
Binary Search
Implement a function that performs binary search on an array of numbers
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
4.43k done
Binary Search Tree
Implement a binary search tree data structure including essential BST operations
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
46 done
Binary Tree
Implement a binary tree data structure including essential operations
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
37 done
Breadth-first Search
Implement a breadth-first search algorithm that traverses a directed graph in a breadth-first manner
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
2.05k done
Depth-first Search
Implement a depth-first search algorithm that traverses a directed graph in a depth-first manner
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.83k done
Is the Graph a Tree
Implement a function to determine if a graph is a valid tree
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
208 done
Heap Sort
Implement a function that performs a heap sort
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
648 done
Maximum Water Trapped Between Walls
Implement a function to find the maximum water volume between two walls in an array of walls
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
319 done
Queue
Implement a queue data structure containing the common queue methods
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.96k done
Dijkstra's Algorithm
Implement Dijkstra's algorithm to find the shortest paths from a source vertex in a graph represented as an adjacency list.
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
12 done
Linked List
Implement a linked list data structure containing the common linked list methods
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
38 done
Merge Sort
Implement a function that performs a recursive merge sort
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.04k done
Quick Sort
Implement a function that performs a recursive quick sort
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
842 done
Topological Sort
Implement a function that performs a topological sort
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
325 done
Maximum Sum in Contiguous Array
Implement a function to find the subarray with the maximum sum
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.12k done
Smallest element in rotated sorted array
Implement a function to find the smallest element in rotated sorted array
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
589 done
Binary Tree Level Order Traversal
Implement a function to find the level order traversal of a binary tree
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
412 done
Maximum Product in Contiguous Array
Implement a function to find the subarray which has the largest product
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
1.08k done
Find Element in Rotated Array
Implement a function to find an integer in a rotated sorted array
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
614 done
Most Common Elements
Implement a function to determine the most common elements in an integer array
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
983 done
Binary Search Tree Kth Smallest Element
Implement a function to find the kth smallest node in a BST
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
466 done
Binary Search Tree Lowest Common Ancestor
Implement a function to find the LCA in a binary search tree
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
380 done
Validate Binary Search Tree
Implement a function to validate whether a binary tree is a valid binary search tree
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
405 done
Count Islands in a Grid
Implement a function to count distinct islands in a 2D binary grid
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
230 done
Distinct Paths in Grid
Implement a function to calculate distinct paths for a robot moving on an m x n grid
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
171 done
Merge Overlapping Intervals
Implement a function to merge overlapping intervals
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
254 done
Delete Nth Node from End of Linked List
Implement a function to delete the nth node from the end of a linked list
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
216 done
Rearrange Linked List
Implement a function to rearrange the nodes in a linked list
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
146 done
Matrix Zeroing
Implement a function to set matrix rows and columns to zero
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
117 done
Neighborhood Theft
Implement a function to find maximum money to rob without alerting police
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
184 done
Sum Without Addition
Implement a function to find the sum of two integers without using + and - operator
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
108 done
Triplet Sum
Implement a function to find all unique triplets with distinct indices that sum to 0
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
174 done
Minimum Coins for Change
Implement a function to return minimum coins needed to make the given amount
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
253 done
Combinations for Target Sum
Implement a function to count combinations that sum to the target
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
199 done
Course Dependency
Implement a function to check if all courses can be completed given prerequisites
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
200 done
Longest Consecutive Number Sequence
Implement a function to find the length of the longest consecutive number sequence
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
186 done
Longest Increasing Subsequence
Implement a function to find the length of the longest increasing subsequence
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
158 done
String Anagram Groups
Implement a function to group an array of strings into anagrams
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
293 done
Decode Message
Implement a function to count ways to decode a numeric string
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
117 done
Palindromic Substrings
Implement a function to count all palindromic substrings in a string
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
166 done
Segment Words
Implement a function to check whether a string be formed from dictionary words
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
123 done
Task Coordination
Implement a function to find minimum intervals for tasks with cooldown
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
83 done
Trie (Prefix Tree)
Implement a trie-prefix-tree with insert, search, and starts with functionality
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
104 done
End of Array Reachable
Implement a function to determine if the end of the array is reachable
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
591 done
Binary Tree Rebuilding from Preorder and Inorder Traversals
Implement a function to construct a binary tree from preorder and inorder traversals
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
184 done
Disjoint Intervals
Implement a function to determine the minimum amount of removals to get non-overlapping intervals
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
171 done
Graph Count Connected Components
Implement a function to count connected components in a graph
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
140 done
Find Word in Grid
Implement a function to check the existence of a word in a grid
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
147 done
Merge New Interval
Implement a function to insert a new interval in the given intervals
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
187 done
Longest Common Subsequence
Implement a function to find the longest common subsequence in two strings
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
162 done
Longest Non-repeating Substring
Implement a function to find the length of longest substring with unique characters
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
218 done
Find the Longest Palindromic Substring
Implement a function to find the longest palindromic substring
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
159 done
Longest Repeating Substring After Replacements
Implement a function to find the longest uniform substring after up to k replacements
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
111 done
Matrix Rotation
Implement a function to rotate the given matrix by 90 degrees
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
110 done
Matrix Spiral Traversal
Implement a function to traverse the matrix in spiral order
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
99 done
Neighborhood Theft (Circular)
Implement a function to find maximum money to rob in circular houses without alerting police
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
118 done
Ocean Flow
Implement a function returning cells with water flow to both oceans
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
80 done
Word Finder
Implement a data structure where words can be added and support wildcard searching
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
92 done
Graph Clone
Implement a function to deeply clone a connected and undirected graph
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
155 done
Minimum Meeting Rooms Needed
Implement a function to find the minimum number of required conference rooms
Algorithmic coding
Algo coding
Difficulty
Medium
Languages
Users completed
196 done
Heap
Implement a heap data structure containing essential heap operations
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
18 done
Binary Tree Serialization and Deserialization
Implement a function to serialize and deserialize a binary tree
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
128 done
Binary Tree Maximum Total Path
Implement a function to find the maximum total of nodes in a binary tree path
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
202 done
Find Words in Grid
Implement a function to find all the words present in the grid
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
70 done
Linked Lists Combine K Sorted
Implement a function to combine k sorted linked lists
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
93 done
Shortest Substring Containing Characters
Implement a function to return the smallest substring of a string containing all characters from another string
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
48 done
Extraterrestrial Language
Implement a function to verify and return an extraterrestrial language's alphabet order
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
54 done
Number Stream Median
Implement a function to find the median of a dynamic stream of integers
Algorithmic coding
Algo coding
Difficulty
Hard
Languages
Users completed
68 done