100 Days Leetcode Challenge

Hi Geeks! Welcome to 100 Days Leetcode challenge. In these days, we going to solve Leetcode’s top 100 data structures and algorithm problems.

Purpose of 100 Days Leetcode Challenge

  • The main purpose of this challenge is, as a Software Developer we should have a strong command over the algorithms and data structures.
  • Solving these problems daily, might helps you to build your logical skills sharply.
  • Because of these skills, at the time of developing applications, you can able to see the differences in the quality of your code from other peers.
  • Logical skills plays a key role in the performance of an application.

How we going to do this challenge

  • For every day, we going to solve only one problem.
  • I want everyone to spend at least 30 minutes daily for this challenge.
  • Therefore, at the end of 100th we will complete 100 Leetcode problems.

In this article, I listed below 100 Leetcode problem questions.

What I’m going to do here?

Everyday, I’m gonna to solve the problem and cover it with detailed explanations and diagrams. My intention here is to solve problems and explain problems with detailed illustrations. But I’m very much interested in explaining the data structures and algorithm problems to newbies.

So I made this article, to help other programmers. Whenever I solve problem, I update here the problem with solutions and explanations.

If you like to join with me, please follow me via email. So that, whenever I solve problems and update here, you will get an email notification message.

Thank you!

100 Days of Leetcode challenge

  1. Top K Frequent Elements   – Completed
  2. Product of Array Except Self    – Completed
  3. Subsets – Completed
  4. Evaluate Reverse Polish Notation  – Completed
  5. Sqrt(x) – Completed
  6. Rotate Array  – Completed
  7. Reverse Bits – Completed
  8. Squares of a Sorted Array – Completed    
  9. Find the Missing Number in an Array – Completed  
  10. Count and Say – Completed
  11. Maximum Depth of Binary Tree – Completed
  12. Sort Characters By Frequency  – Completed
  13. How to Reorganize String? – Completed
  14. Alphabet Board Path – Completed
  15. Minimum Remove to Make Valid Parentheses – Completed    
  16. How Many Numbers Are Smaller Than the Current Number – Completed
  17. Find all Duplicates in an Array – Completed
  18. First Missing Positive – Completed
  19. Implement Queue using Stacks – Completed
  20. Implement Stack using Queues – Completed
  21. Implement LRU Cache – Completed
  22. Binary Tree Inorder Traversal – Completed 
  23. Binary Tree Preorder Traversal – Iterative way – Completed
  24. Root To Leaf Sum Binary Tree – Completed
  25. Invert Binary Tree – Completed
  26. Average of Levels in Binary Tree – Completed
  27. Binary Tree Level Order Traversal II – Completed
  28. Happy Number – Completed
  29. Maximum sub array – Completed
  30. Find Largest Value in Each Tree Row – Completed
  31. Move Zeroes – Completed
  32. Reverse Substrings Between Each Pair of Parentheses – Completed
  33. Group Anagrams – Completed
  34. Path Sum II – Completed
  35. Binary Tree Paths – Completed
  36. Binary Tree Right Side View – Completed
  37. Binary Tree Level Order Traversal – Completed
  38. Binary Tree Zigzag Level Order Traversal – Completed
  39. Best Time to Buy and Sell Stock II – Completed
  40. Binary Search Tree: Insertion – Completed
  41. Min Stack : Push O(1), Pop O(1), GetMin O(1) – Completed
  42. How to Validate Binary Search Tree – Completed
  43. How to find the Height and Diameter of the Binary Tree – Completed
  44. Find Bottom Left Tree Value – Completed
  45. Convert Sorted Array to Binary Search Tree – Completed
  46. Sum Root to Leaf Numbers – Completed
  47. Perform String Shifts – Completed
  48. Sum of Left Leaves Iterative and Recursive Approach – Completed
  49. Reverse Vowels of a String – Completed
  50. Set Matrix Zeroes – Completed
  51. Minimum Depth of Binary Tree – Completed
  52. Valid String Parenthesis – Completed
  53. Binary Search Tree Iterator – Completed
  54. Find the Duplicate Number (Hare and Tortoise) – Completed 
  55. Longest Substring Without Repeating Characters – Completed
  56. First Unique Number – Completed
  57. Diagonal Traverse II – Completed
  58. Cousins in Binary Tree – Completed
  59. Check If It Is a Straight Line – Completed
  60. Contains Duplicate II – Completed
  61. Find the Town Judge – Completed
  62. Maximal Square – Completed
  63. Minimum Edit Distance – Completed
  64. Longest Increasing Subsequence – Completed   
  65. Insert Delete GetRandom O(1) – Completed
  66. Count Square Submatrices with All Ones – Completed
  67. Insert Interval – Completed
  68. Climbing Stairs – Completed
  69. Merge k Sorted Lists – Completed
  70. Path In Zigzag Labelled Binary Tree – Completed
  71. 4Sum II – Completed
  72. Find First and Last Position of Element in Sorted Array – Completed
  73. Coin Change – Completed
  74. Lexicographical Numbers : Beauty of DFS – Completed
  75. Unique Binary Search Trees : Catalan Numbers – Completed
  76. Word Break – Completed
  77. Rotate Function – Completed
  78. Best Time to Buy and Sell Stock – Easy Problem – Completed
  79. Largest Rectangle in Histogram – Completed
  80. Container With Most Water – Completed
  81. Minimum Jumps – Completed 
  82. Count Subsequences – Completed
  83. Max Sum K – Partition – Completed 
  84. Palindromic Queries – Completed
  85. 3Sum
  86. Surrounded Regions  
  87. Decode Ways
  88. Fraction to Recurring Decimal
  89. Divide Two Integers 
  90. String to Integer (atoi) 
  91. Trapping Rain Water
  92. Serialize and Deserialize Binary Tree
  93. Longest Consecutive Sequence
  94. Longest Increasing Path in a Matrix 
  95. Find Median from Data Stream 
  96. Sliding Window Maximum
  97. Count of Smaller Numbers After Self
  98. Merge k Sorted Lists 
  99. Largest Rectangle in Histogram
  100. Minimum Window Sub-string

What are the languages I’m going to use?

Since programming languages are independent of data structures and algorithms. So I’m going to play with data structures and algorithms using Java, JavaScript and C#.

8 thoughts on “100 Days Leetcode Challenge

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