Leetcode-Problem-Solving

📝 A collection of LeetCode problems I’ve solved. 💡 Solutions with explanations to understand the approach. 🚀 Organized by difficulty and problem type. 🎯 Practicing daily to get better at algorithms and data structures. 🔗 Feel free to explore, learn, and suggest improvements!

Day 1

• Solved LeetCode Problem 15: 3Sum
• Approach: Two-pointer technique
• Handled edge cases:
  • Array/List size less than 3
  • Duplicate elements

Day 2

• Solved LeetCode Problem 16: 3Sumclosest
• Approach: Two-pointer technique
• Handled edge cases:
  • Array/List size less than 3
  • Duplicate elements
  • Updating the closest_sum when there is a best difference.

Day 3

• Solved LeetCode Problem 18: 4Sum
• Approach: Two-pointer technique
• Handled edge cases:
  • Array/List size less than 4
  • Duplicate elements
  • Updating the two pointers and storing valid quadruplets.

Day 4

• Solved LeetCode Problem 11: Container with most water
• Approach: Two pointer approach
• Handled edge cases:
  • Computing max_area based on minimum height from the left or right.
  • Updating the two pointers and storing valid max_area.

Day 5

• Solved LeetCode Problem 31: Finding the next permutation
• Approach: Two pointers and swapping
• Handled edge cases:
  • Finding first drop in the list.
  • Swapping the elements.
  • Reversing the right part of list.

Day 6

• Solved LeetCode Problem 35: Search insert position
• Approach: Binary Search
• Handled edge cases:
  • Finding the element based mid value.
  • The last value of left index the expected index.

Day 7

• Solved LeetCode Problem 3: Finding longest substring without repeating character
• Approach: Sliding Window
• Handled edge cases:
  • Finding the longest substring using sliding window and HashTable.
  • The shrinking or expandng window using two pointers.

Day 8

• Solved LeetCode Problem 49: Finding anagrams
• Approach: Sorting and Hashtable(dictionary)
• Handled edge cases:
  • Using a defaultdict() from collections to create a dictionary of values stored as list.
  • Finding the key for dictionary using join() and sorted() methods.
  • Returning the list of values.

Day 9

• Solved LeetCode Problem 33: Searching in sorted and rotated array
• Approach: Binary search
• Handled edge cases:
  • Finding which half is sorted.
  • Finding which pointer to move(left or move).
  • Returning -1 if the element is not found.