Programming Challenges

LeetCode

Challenge	Solution	Difficulty	Observations
1. Two Sum	two_sum.py	Easy
2. Add Two Numbers	AddTwoNumbers.kt AddTwoNumbers2.kt	Medium	Version 2 was a failed attempt. Runtime: 252 ms, faster than 89.36% of Kotlin online submissions for Add Two Numbers.
3. Longest Substring Without Repeating Characters	LongestSubstringWithoutRepeatingCharacters.kt	Medium	Runtime: 384 ms, faster than 27.11% of Kotlin online submissions for Longest Substring Without Repeating Characters... :(
4. Median of Two Sorted Arrays	median_of_two_sorted_arrays.c	Hard	The problem requested O(log(m+n)) but this solution is O(m+n)
5. Longest Palindromic Substring	LongestPalindromicSubstring.kt LongestPalindromicSubstring.java	Medium
7. Reverse Integer	ReverseInteger.kt	Easy
11. Container With Most Water	ContainerWithMostWater.java	Medium	Runtime: 4 ms, faster than 99.26%
15. 3Sum	3Sum.kt	Medium
22. Generate Parentheses	GenerateParentesis.kt	Medium
46. Permutations	permutations.c	Medium
49. Group Anagrams	GroupAnagrams.java	Medium
65. Valid Number	ValidNumber.java	Hard
73. Set Matrix Zeroes	SetMatrixZeroes.java	Medium
104. Maximum Depth of Binary Tree	MaximumDepthOfBinaryTree.cpp	Easy
124. Binary Tree Maximum Path Sum	max_path_sum.c	Hard	Solution by shichaotan
136. Single Number	single_number.cpp	Easy
146. LRU Cache	lru_cache.c	Hard	Hash table with linked elements, organized through pointer manipulation
155. Min Stack	min_stack.c	Easy
160. Intersection of Two Linked Lists	IntersectionOfTwoLinkedLists.java	Easy
297. Serialize and Deserialize Binary Tree	SerializeAndDeserializeBinaryTree.java	Hard
328. Odd Even Linked List	OddEvenLinkedList.kt	Medium
338. Counting Bits	counting_bits.cpp	Medium
380. Insert Delete GetRandom O(1)	InsertDeleteGetRandomO1.java	Medium
406. Queue Reconstruction by Height		Medium	Solution
461. Hamming Distance	hamming_distance.py	Easy
581. Shortest Unsorted Continuous Subarray	shortest_unsorted_continuos_subarray.c	Easy	Inspired by compton_scatter solution
617. Merge Two Binary Trees	MergeTwoBinaryTrees.kt	Easy

CodinGame

Challenge	Solution	Difficulty
ASCII Art	AsciiArt.java	Easy
Chuck Norris	chuck_norris.c	Easy
Mars Lander - Episode 1	mars_lander_episode_1.c	Easy
Onboarding	onboarding.py	Easy
Power of Thor - Episode 1	power_of_thor_episode_1.c	Easy
Temperatures	temperatures.c	Easy
The Bridge - Episode 1	the_bridge_episode_1.c	Easy
There is no Spoon - Episode 1	ThereIsNoSpoonEpisode1.java	Medium

/r/dailyprogrammer/

Challenge	Solution	Difficulty
Maze To Graph	MazeToGraph.java	Medium
Escaping a dangerous maze	MazeRunner.java	Hard

Google Code Jam

Challenge	Solution	Difficulty
Alphabet Cake	alphabet_cake.py	Round 1A 2017

HackerRank

Cracking the Coding Interview

Challenge	Solution	Difficulty
Linked Lists: Detect a Cycle	detect_a_cycle.py	Easy
Hash Tables: Ransom Note	ransom_note.py	Easy
Arrays: Left Rotation	left_rotation.c	Easy
Strings: Making Anagrams	MakingAnagrams.java	Easy
Recursion: DP: Fibonacci Numbers	fibonacci.py	Easy
Bit Manipulation: Lonely Integer	lonely_integer.py	Easy
Stacks: Balanced Brackets	balanced_brackets.c	Medium
Trees: Is This a Binary Search Tree?	BST.java	Medium
Queues: A Tale of Two Stacks	two_stacks.c	Medium
Sorting: Bubble Sort	bubble_sort.c	Medium
Sorting: Comparator	Checker.java	Medium
Time Complexity: Primality	primality.py	Medium
Recursion: DP: Davis' Staircase	davis_staircase.py	Medium
Binary Search: Ice Cream Parlor	ice_cream.py	Medium
Tries: Contacts	Contacts.java	Hard
DFS: Connected Cell in a Grid	connected_cell.c	Hard
Merge Sort: Counting Inversions	counting_inversions.c	Hard
Heaps: Find the Running Median	running_median.c	Hard
DP: Coin Change	coin_change.py	Hard
BFS: Shortest Reach in a Graph	shortest_reach.py	Hard

Advent of Code 2015

Challenge	Part 1	Part2
Day 1: Not Quite Lisp	day_1_a.cpp	day_1_b.cpp
Day 2: I Was Told There Would Be No Math	day_2_a.cpp	day_2_b.cpp
Day 3: Perfectly Spherical Houses in a Vacuum	day_3_a.cpp	day_3_b.cpp
Day 4: The Ideal Stocking Stuffer	day_4_a.cpp	day_4_b.cpp
Day 5: Doesn't He Have Intern-Elves For This?	day_5_a.cpp	day_5_b.cpp
Day 6: Probably a Fire Hazard	day_6_a.cpp	day_6_b.cpp
Day 7: Some Assembly Required	day_7_a.cpp	day_7_b.cpp

Advent of Code 2018

Challenge	Part 1	Part2
Day 1: Chronal Calibration	day_1_a.kt	day_1_b.kt
Day 2: Inventory Management System	day_2_a.kt	day_2_b.kt
Day 3: No Matter How You Slice It	day_3_a.kt	day_3_b.kt
Day 4: Repose Record	day_4_a.kt	day_4_b.kt
Day 5: Alchemical Reduction	day_5_a.kt	day_5_b.kt
Day 6: Chronal Coordinates	day_6_a.kt	day_6_b.kt
Day 7: The Sum of Its Parts	day_7_a.kt	day_7_b.kt
Day 8: Memory Maneuver	day_8_a.kt	day_8_b.kt
Day 9: Marble Mania	day_9_a.kt	day_9_b.kt
Day 10: The Stars Align	day_10_a.kt	day_10_b.kt
Day 11: Chronal Charge	day_11_a.kt	day_11_b.kt
Day 12: Subterranean Sustainability	day_12_a.kt	day_12_b.kt