154 Problems
215 Problems
105 Problems
Evaluate Postfix Notation
Decode Numbers!
Circular route
Minimum Window Sequence
POW!
Find the Max Element in a Binary Tree Recursively
Binary Search on Array of Integers
Horizontal Flip
Validate a Sudoku
Binary Representation
Graph Depth First Search
Are these Binary Trees Identical?
Check Balanced Parentheses
Merge Two Sorted Arrays
Even Split
Robbery
Reverse a Singly Linked List
Binary Tree Serialization
1-800-PROBLEM
Find the Lowest Common Ancestor of Two Tree Nodes
Division
Replace all Spaces
Find the Number that Appears Once
Add Two Linked List-ish Numbers
Implement the Breadth First Search Algorithm for a Graph
Insert a Node at the End of a Linked List
Longest Common Prefix in a group of Strings
Wildcard Pattern Matching
Print Paths
BST Validation
Number of Half Nodes in a Binary Tree
Maximum Coordinates!
Rotate a Square Image Clockwise
Binary Gap
Delete a Circular-Linked List's Tail Node
Iterative Inorder Traversal
Find the Maximum BST Node
Better Fibonacci
Repeated Sequences(DNA)
Insert Stars
Reverse a string
Max Gain
Bit Conversion
Minimum number of Jumps
Longest substring with two Unique Characters
Simplify file Path
Find the Maximum Contiguous Subsequence in an Array
Mobile Game Range Module - Inserting Ranges
Boggle Search
Recursively Merge Two Sorted Linked Lists
Find the Transpose of a Square Matrix
Delete a List's Tail Node
Check a Linked List for Loops or Cycles With O(1) Space Complexity
Find the Minimum BST Node
Sorted Array into BST
Convert a Binary Tree to its Mirror Image
Sorted Linked List into BST
Merge array into the Largest Number
Compare Two Versions
Re-arrange Linked List in Pairs
Iterative Preorder Traversal
Full Tree Decompression
Number of Full Nodes in a Binary Tree
Anagrams
Repeated Elements in an Array
Boggle with Paper Dictionary
Find the k^{th} Largest Node in a BST
Longest Non-Repeating Substring
Steal the Node
Maximum Sum Path
Find the Level that has the Maximum Sum
Matrix Max Sum Path with DFS
Stock Market Oracle
Delete the Node at the Specific Position in a Doubly Linked List
Fibonacci Number
Delete a List's Head Node
Find a Node in a Binary Tree Without Using Recursion
Introduction to Tries
Find the Sum of all Elements in a Binary Tree
Even or Odd?
Insert a Node at the Front of a Linked List
Count the Leaves!
Subset Summation
Recursive String Permutation
Rotate Linear Array
Reverse Level Order Traversal
Distance between two nodes in a Binary Tree
Delete the Head Node of a Circular Linked List
Merge k Sorted Linked Lists
Insert a Node at the Tail of a Circular Linked List
Couple Sum
Rotate a Square Image Counterclockwise
Find the N^{th} Node from the End - Linked List
Remove the "N^{th} from the end" Node from a Singly-Linked List
Insert a Node at a specified position in a Linked List
Generate Combinations of Parentheses
Image Manipulation
Insert a Node at the Specified Position in Doubly Linked List
Combinations and Permutations
Distance of a node from the root
Snake
Permutations!
Isomorphic Strings
Subset Summation with Number Constraint
Boggle with Electronic Dictionary
Iterative BST Validation
Find the Missing Number in a Set of Numbers from 1 to 10
Flip it!
Find the First Non Duplicate Character in a String
Mirror Mirror on the Wall ...
Minimum Depth of a Tree
Looping Lists : Space complexity O(n)
Find the k^{th} Smallest Node in a BST
Unique Chars in a String
Reverse an Integer
Palindrome Tester
Reverse a Linked List in Pairs
Largest Square
Find the Middle of a List in a Single Pass
Pascal's Triangle
String Compression
Selection Sort
Fill in the Ancestors of the Node in a Binary Tree
Recovering IPv4 Addresses
N-Ary Tree Serialization
Iteratively, find the Max Element in a Give Binary Tree
Power of 2
Bubble Sort
Mobile Game Range Module - Merging Ranges
Is this List a Palindrome?
Find the N^{th} Node from the end without using extra memory - Linked List
Find the Maximum Number of Repetitions
Print all Possible Characters
Delete the Node at a Particular Position in a Linked List
Remove Duplicate Nodes
Is this Integer a Palindrome?
Insert a Node at the Head in a Doubly Linked List
Insert a Node at the Tail of a Doubly Linked List
Insert a Node at the Head of a Circular Linked List
Delete the Node at the Head of a Doubly Linked List
Delete the Tail Node of a Doubly Linked List
Recursive Preorder Traversal
Recursive Inorder Traversal
Recursive Postorder Traversal
Iterative Postorder Traversal
Levelorder Traversal
Find the size of the Binary Tree
Print a Binary Tree Level by Level
Roll the Dice!
Making Change
Parse Simple Mathematical Expressions
Natural Language Parser
Does an Element N Exist in a Given Binary Tree?
The Deepest Node
Height of a Binary Tree
Find the Sum of all Elements in a Binary Tree Iteratively
Jam into a BST
Find a BST Node
Print all Nodes in the Range a .. b in a given BST
Find the Diameter of a BST
Bit Swapping
Implement the Depth First Search traversal Algorithm in a Grap
Implement Breadth First Search Traversal Algorithm in a Grap
Implement the Djikstra Shortest Path Algorithm in a Graph
Reverse Words with Punctuation
Implement a Least Recently Used (LRU) Cache
Binary Tree Subsets with Same Sum
Balanced Braces
Remove Duplicates from a List of Words
Count 1
s in a Binary Representation
Knapsack Algorithm
Merge Two Sorted Integer Arrays in Linear Time
Addition of Binary Strings
Iterator of Binary Search Tree with Nodes Containing Integer Data
Day with Maximum Difference in Temperatures
Soccer Team with Minimum Difference in Goals
Path between Two Input Words in a Dictionary
A million lines of code!
Tail N Number of Lines from an Input File
Add Two Numbers without using Plus Sign
Integer to Roman
Longest Consecutive Integers Set in an Array
Multiplication of Arrays
First N Prime Numbers
Rotate an Array to the Right.
Minimum Sum Path
Happy Numbers!
Flip bits in a matrix
Minimum Sum Path in a Triangle
Array Partition
Duplicate neighbours
Tail word length
Dominant Element
Merge Integer Ranges
Insert and Merge Ranges
Look and Say Sequence
Triple Sum
Quadruple Sum
Find Needle in a Haystack
Minimum Sub Array Size for a Target
Make Palindrome
Sum Root-to-Leaf Numbers
Range of a Number in an Array
Rightmost Nodes of a Tree
Fraction to Decimal
Excel - Column Name to Number
Excel - Column Number to Column Name
Chocolate time!
Unique Routes!
Break a Word!
Count Paths on a Game Board
Longest Palindromic Substring
HashMap with Random Value Picker
Matrix Max Sum Path with Dynamic Programming
Word Similarity - Edit Distance
C
Java
Python