Challenges list

• Challenge 1: Spirally traversing a matrix
• Challenge 2: Largest subset whose all elements are Fibonacci numbers
• Challenge 3: Pair with sum = k
• Challenge 4: Inplace rotate square matrix by 90 degrees
• Challenge 5: Product of every position
• Challenge 6: Serialize/Deserialize binary tree
• Challenge 7: First missing positive integer
• Challenge 8: Rearrange a string in sorted order followed by the integer sum
• Challenge 9: Find square with max sum
• Challenge 10: Find year with max population alive
• Challenge 11: Convert ternary expression to a binary tree
• Challenge 12: Count possible decodings of a given digit sequence
• Challenge 13: Find K smallest elements in an array
• Challenge 14: Implement an autocomplete system
• Challenge 15: Unique ways to climb a staircase
• Challenge 16: Add two numbers as a linked list
• Challenge 17: Longest substring without repeating characters
• Challenge 18: Longest palindromic substring
• Challenge 19: First and last indices of an element in a sorted array
• Challenge 20: Reverse a linked list
• Challenge 21: Sorting a list with 3 unique numbers
• Challenge 22: Two-Sum
• Challenge 23: Invert a binary tree
• Challenge 24: Move zeros
• Challenge 25: Falling Dominoes
• Challenge 26: Course Pre-requisites
• Challenge 27: Witness of The Tall People
• Challenge 28: Validate BST
• Challenge 29: Flood fill
• Challenge 30: Merge sort
• Challenge 31: Find cycle in indirected graph
• Challenge 32: Shortest path in a indirected acyclic graph
• Challenge 33: Merge Overlapping Intervals
• Challenge 34: Subset sum problem
• Challenge 35: Count rectangles
• Challenge 36: Maximum Profit From Stocks
• Challenge 37: Active time
• Challenge 38: Remove k-th Last Element From Linked List
• Challenge 39: Remove Consecutive Nodes that Sum to 0
• Challenge 40: Queue Using Two Stacks
• Challenge 41: Maximum sequence of consecutive numbers
• Challenge 42: Depth of a stringified binary tree
• Challenge 43: Contiguous Subarray with Maximum Sum
• Challenge 44: Find the k-th Largest Element in a List
• Challenge 45: Occurrences of a number in a sorted array
• Challenge 46: Sudoku solver
• Challenge 47: Closest coin
• Challenge 48: Median of window
• Challenge 49: Buddy strings
• Challenge 50: Create a balanced binary search tree
• Challenge 51: Subsequences of string
• Challenge 52: Deepest Node in a Binary Tree
• Challenge 53: Thousand missing numbers
• Challenge 54: Find the number of islands
• Challenge 55: Merge list of number into ranges
• Challenge 56: Find largest BST
• Challenge 57: Arithmetic Binary Tree
• Challenge 58: Get all Values at a Certain Height in a Binary Tree
• Challenge 59: Sort Colors
• Challenge 60: Group anagrams
• Challenge 61: Full Binary Tree
• Challenge 62: Palindrome with maximum "k" deletions
• Challenge 63: Jump to the end
• Challenge 64: Look and Say
• Challenge 65: Free slots in calendar
• Challenge 66: Level Order Traversal of Binary Tree