LeetCode Cheat Sheet

A “LeetCode cheat sheet” can be a reference for various programming techniques and common problem-solving patterns encountered on the LeetCode platform. Here’s a cheat sheet that covers some essential concepts and tips:

Problem Solving Techniques

  • Two Pointers:
    • Use two pointers to traverse the array or list efficiently.
  • Sliding Window:
    • Maintain a subarray or sublist satisfying certain conditions while iterating through the array or list.
  • Binary Search:
    • Divide and conquer to efficiently search for an element in a sorted array or list.
  • Depth-First Search (DFS):
    • Explore as far as possible along each branch before backtracking.
  • Breadth-First Search (BFS):
    • Explore a graph level by level, typically using a queue.

Data Structures

  • Arrays:
    • Master array manipulation, sorting, and searching.
  • Linked Lists:
    • Solve problems involving linked list traversal, manipulation, and cycle detection.
  • Trees:
    • Understand binary tree traversal, BST properties, and tree manipulation.
  • Stacks and Queues:
    • Solve problems requiring LIFO (Last In, First Out) or FIFO (First In, First Out) behavior.
  • Hash Tables:
    • Use hash tables for efficient data lookup.
  • Heaps:
    • Understand heap properties and solve problems related to priority queues.

Dynamic Programming

  • Dynamic Programming Basics:
    • Identify overlapping subproblems and optimal substructure.
  • Memoization and Tabulation:
    • Use memoization (top-down) or tabulation (bottom-up) for optimization.

String Manipulation

  • String Reversal:
    • Reverse strings using different techniques.
  • Substring Matching:
    • Implement algorithms for substring searching.
  • Anagrams:
    • Check if two strings are anagrams.

Math and Bit Manipulation

  • Prime Numbers:
    • Implement algorithms related to prime numbers.
  • Bitwise Operations:
    • Master bitwise manipulation for efficient solutions.
  • GCD and LCM:
    • Solve problems involving the Greatest Common Divisor (GCD) and Least Common Multiple (LCM).

Additional Tips

  • Edge Cases:
    • Consider edge cases and boundary conditions.
  • Optimization:
    • Optimize your solution for time and space complexity.
  • Understand Constraints:
    • Be aware of time and space constraints mentioned in the problem description.
  • Read and Understand the Problem:
    • Carefully read the problem statement and clarify doubts before starting.
  • Test Your Code:
    • Test your code with sample inputs and edge cases.
  • Learn from Discussions:
    • Explore and learn from the discussions section for different approaches.

Remember, consistent practice is key to improving your problem-solving skills on LeetCode. Adjust your strategies based on the type of problem and always strive for clean, efficient, and correct solutions.