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  • Leetcode Top Interview ๐ŸŽฏ
  • Guide to Calculating Algorithm Complexity ๐Ÿš€
  • Topic 1 Array - String
    • 88. Merge Sorted Arrays ๐Ÿงฉ
    • 27. Remove Element ๐Ÿงน
    • 26. Remove Duplicates from Sorted Array ๐Ÿšซ
    • 80. Remove Duplicates from Sorted Array II ๐Ÿšซ๐Ÿšซ
    • 169. Majority Element ๐Ÿ‘‘
    • 189. Rotate Array ๐Ÿ”„
    • 121. Best Time to Buy and Sell Stock ๐Ÿ“ˆ
    • 122. Best Time to Buy and Sell Stock II ๐Ÿ“ˆ๐Ÿ’ฐ
    • 55. Jump Game ๐Ÿƒโ€โ™‚๏ธ
    • 45. Jump Game II ๐Ÿƒโ€โ™‚๏ธ
    • 274. H-Index ๐Ÿ“Š
    • 380. Insert Delete GetRandom O(1) ๐ŸŽฒ
    • 238. Product of Array Except Self ๐Ÿ”„
    • 134. Gas Station โ›ฝ
    • 135. Candy ๐Ÿฌ
    • 42. Trapping Rain Water ๐ŸŒง๏ธ
    • 13. Roman to Integer ๐Ÿ”ข
    • 018 Integer to Roman
    • 58. Length of Last Word ๐Ÿ” 
    • 14. Longest Common Prefix ๐ŸŒฑ
    • 151. Reverse Words in a String ๐Ÿ”„
    • 6. Zigzag Conversion ๐Ÿ”€
    • 28. Find the Index of the First Occurrence in a String ๐Ÿ”„
    • 68. Text Justification ๐Ÿ”„
  • Topic 2 Two Pointers
    • 125. Valid Palindrome ๐Ÿšฆ
    • 392. Is Subsequence ๐Ÿ“
    • 167. Two Sum II - Input Array Is Sorted ๐Ÿ”
    • 11. Container With Most Water ๐Ÿž๏ธ
    • 15. 3Sum ๐ŸŒ
  • Topic 3 Sliding Window
    • 209. Minimum Size Subarray Sum ๐ŸŒ
    • 3. Longest Substring Without Repeating Characters ๐ŸŒ
    • 30. Substring with Concatenation of All Words ๐ŸŒ
    • 76. Minimum Window Substring ๐ŸŒ
  • Topic 4 Matrix
    • 36. Valid Sudoku ๐ŸŒ
    • 54. Spiral Matrix ๐ŸŒ
    • 48. Rotate Image ๐Ÿ”„
    • 73. Set Matrix Zeroes
    • 289. Game of Life ๐Ÿ–ผ๏ธ
  • Topic 5 Hashmap
    • 383. Ransom Note ๐Ÿ”
    • 205. Isomorphic Strings ๐Ÿ”
    • 290. Word Pattern ๐Ÿงฉ
    • 242. Valid Anagram ๐ŸŽข
    • 49. Group Anagrams ๐Ÿคนโ€โ™‚๏ธ
    • 1. Two Sum ๐Ÿ”
    • 202. Happy Number ๐Ÿคฉ
    • 219. Contains Duplicate II ๐Ÿ”
    • 128. Longest Consecutive Sequence ๐Ÿ”
  • Topic 6 Intervals
    • 228. Summary Ranges ๐Ÿ“Š
    • 56. Merge Intervals ๐Ÿ”€
    • 57. Insert Interval ๐Ÿ†•
    • 452. Minimum Number of Arrows to Burst Balloons ๐ŸŽˆ
  • Topic 7 Stack
    • 20. Valid Parentheses ๐Ÿ”
    • 71. Simplify Path ๐Ÿ—บ๏ธ
    • 155. Min Stack ๐Ÿ—ƒ๏ธ
    • 150. Evaluate Reverse Polish Notation ๐Ÿง ๐Ÿ’ป
    • 224. Basic Calculator ๐Ÿงฎ
  • Topic 8 Linked List
    • 141. Linked List Cycle ๐Ÿ”
    • 2. Add Two Numbers ๐Ÿ”ข
    • 21. Merge Two Sorted Lists ๐Ÿ”—
    • 138. Copy List with Random Pointer ๐Ÿ”—
    • 92. Reverse Linked List II ๐Ÿ”„
      • Letโ€™s explain step by step ๐Ÿ‡
    • 25. Reverse Nodes in k-Group ๐Ÿ”„
    • 19. Remove Nth Node From End of List ๐Ÿ—‘๏ธ
    • 82. Remove Duplicates from Sorted List II โŒ๐Ÿ”ข
    • 61. Rotate List ๐Ÿ”„
    • 86. Partition List ๐Ÿ”—
    • 146. LRU Cache ๐Ÿ”—
  • Topic 9 Binary Tree General
    • 104. Maximum Depth of Binary Tree ๐Ÿ”—
    • 100. Same Tree ๐Ÿ”—
    • 226. Invert Binary Tree ๐Ÿ”—
    • 101. Symmetric Tree ๐Ÿ”—
    • 105. Construct Binary Tree from Preorder and Inorder Traversal ๐Ÿ”—
    • 106. Construct Binary Tree from Inorder and Postorder Traversal ๐Ÿ”—
    • 117. Populating Next Right Pointers in Each Node II ๐Ÿ”—
    • 114. Flatten Binary Tree to Linked List ๐Ÿ”—
    • 112. Path Sum ๐Ÿ”—
    • 129. Sum Root to Leaf Numbers ๐Ÿ”—
      • What_is_DFS
    • 124. Binary Tree Maximum Path Sum ๐Ÿ”—
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  • ๐Ÿ“Œ Fundamental in Algorithmic Problem Solving Array & String
  • 1. Basic Array & String processing ๐Ÿ“–
  • 2. Sorting ๐Ÿงน
  • 3. Greedy ๐Ÿ€
  • 4. Simulation ๐ŸŽฎ
  • 5. Prefix Sum Design ๐Ÿ”ข
  • 6. Hash Table ๐Ÿ—‚
  • 7. Randomized ๐ŸŽฒ
  • 8. Dynamic Programming (DP) ๐Ÿ”„
  • 9. Breadth-First Search (BFS) ๐ŸŒ
  • 10. Mathematics ๐Ÿ“
  • ๐Ÿš€ Applications in Algorithmic Problem Solving
  • ๐Ÿ Conclusion

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Topic 1 Array - String

PreviousGuide to Calculating Algorithm Complexity ๐Ÿš€Next88. Merge Sorted Arrays ๐Ÿงฉ

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Arrays and strings are foundational structures in computer science and algorithmic problem solving. They are often used to model real-world data and come with a variety of techniques to process, manipulate, and optimize their usage efficiently. Here are key techniques and topics commonly used in problems involving arrays and strings. ๐Ÿš€


๐Ÿ“Œ Fundamental in Algorithmic Problem Solving Array & String

1. Basic Array & String processing ๐Ÿ“–

Arrays and strings are basic data structures where arrays hold a collection of elements, and strings represent sequences of characters. Many algorithmic problems involve processing these structures, such as searching, sorting, and finding optimal subsets or sequences.

Learn More about Array & String Problems:


2. Sorting ๐Ÿงน

Sorting algorithms rearrange elements in a specified order (ascending or descending). Sorting is often used as a preprocessing step for many algorithms to simplify operations like searching, merging, and optimizing.

Learn More about Sorting Algorithms


3. Greedy ๐Ÿ€

Greedy algorithms make the locally optimal choice at each stage, with the hope of finding a global optimum. This technique is used in problems where choosing the best local solution leads to the best overall outcome.

Learn More about Greedy Algorithms


4. Simulation ๐ŸŽฎ

Simulation refers to modeling and mimicking real-world processes step by step. In algorithmic problems, simulation is useful when you need to mimic actions or movements as described by the problem.

Learn More about Simulation in Algorithms


5. Prefix Sum Design ๐Ÿ”ข

Prefix sum is an optimization technique that allows efficient querying of sum ranges in an array. Itโ€™s particularly useful for problems involving range queries, where direct calculations would be too slow.

Learn More about Prefix Sum Design


6. Hash Table ๐Ÿ—‚

A hash table is a data structure that allows for fast access to data via key-value pairs. It is used to store data for quick lookup, insertion, and deletion. Hash tables are particularly useful for problems like finding duplicates or counting occurrences.

Learn More about Hash Tables


7. Randomized ๐ŸŽฒ

Randomized algorithms use randomness as a part of their logic. These algorithms often provide average-case performance guarantees and are used in problems where deterministic solutions are difficult to implement or inefficient.

Learn More about Randomized Algorithms


8. Dynamic Programming (DP) ๐Ÿ”„

Dynamic programming solves problems by breaking them down into simpler subproblems and solving each subproblem just once, storing the results to avoid redundant work. It is widely used in optimization problems.

Learn More about Dynamic Programming


9. Breadth-First Search (BFS) ๐ŸŒ

BFS is an algorithm used to traverse or search through a graph or tree. It explores all the neighboring nodes at the present depth level before moving on to nodes at the next depth level. BFS is essential for finding the shortest path in unweighted graphs.

Learn More about Breadth-First Search


10. Mathematics ๐Ÿ“

Mathematics plays a significant role in algorithmic problem solving, especially in number theory, combinatorics, and geometry. Many problems require mathematical formulas and techniques for optimization or proof.

Learn More about Mathematics in Algorithms


๐Ÿš€ Applications in Algorithmic Problem Solving

  • Array & String Problems

    • Manipulate, search, and optimize subsets of arrays and strings.

  • Optimization

    • Techniques like greedy and dynamic programming are often used for optimization tasks.

  • Graph Traversal

    • BFS and other traversal algorithms help explore graphs in various contexts like pathfinding and connectivity.

  • Efficiency

    • Data structures like hash tables and prefix sum are crucial for solving problems efficiently, reducing time complexity.


๐Ÿ Conclusion

Arrays and strings are essential building blocks in algorithmic problem solving. Mastering techniques like Sorting, Greedy, Dynamic Programming, and more can significantly improve your ability to tackle complex problems efficiently. Dive into each topic to explore their applications and optimize your approach to algorithms. Happy coding! ๐ŸŽฏ

Happy Coding!!

Remove Element
Remove Duplicates from Sorted Array
Remove Duplicates from Sorted Array II
Length of Last Word
Longest Common Prefix
Reverse Words in a String
Find the Index of the First Occurrence in a String
Merge Sorted Array
Majority Element
H-Index
Jump Game
Gas Station
Candy
Text Justification
ZigZag Conversion
Product of Array Except Self
Insert Delete GetRandom
Roman to Integer
Integer to Roman
Insert Delete GetRandom
Best Time to Buy and Sell Stock
Best Time to Buy and Sell Stock II
Trapping Rain Water
Jump Game II
Rotate Array