How to Solve Array Problems in Coding Interviews?

Coding Interviews are easy if you know which trick to apply on the question. Simple!

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In coding interviews, solving problems related to arrays can be done using various techniques and algorithms. Let's take a look at some commonly used methods:

  1. Two Pointers Technique

    This method involves using two pointers to move through the array simultaneously. It helps efficiently find pairs, and subarrays, or meet specific conditions based on array values.

  2. Sliding Window Technique

    Here, you create a fixed-size window and slide it through the array to perform operations efficiently. It's useful for solving problems involving subarrays or substrings.

  3. Prefix Sums

    By calculating the prefix sums of the array beforehand, you can quickly find the sum of elements within a specific range of indices. This is handy for solving problems with frequent range sum queries.

  4. If the array is sorted or has certain properties, binary search can help efficiently find elements or satisfy particular conditions within the array.

  5. Sorting

    Sorting the array can simplify the problem and make it easier to identify patterns or find elements with specific properties.

  6. Hashing

    Using a hash table, you can efficiently store and retrieve elements from the array. It's useful for counting occurrences or checking for duplicates.

  7. Frequency Counting

    Counting the occurrences of elements in the array often reveals patterns or helps identify elements that meet specific conditions.

  8. Greedy Approach

    This involves making locally optimal choices at each step to reach a globally optimal solution.

  9. Dynamic Programming

    Although commonly associated with other data structures, dynamic programming techniques can be applied to array problems in certain cases.

  10. Binary Indexed Tree (Fenwick Tree)

    This data structure is helpful for efficiently performing range queries and updates on an array, especially for cumulative sum operations.

  11. Merge Intervals

    When dealing with intervals in the array, merging overlapping intervals can simplify the problem and make processing easier.

  12. Divide and Conquer

    Breaking the array into smaller subproblems and combining their solutions can be useful for certain situations.

Remember, the best technique to use depends on the specific requirements and constraints of the problem. Familiarizing yourself with these techniques and practicing them on different array problems will improve your ability to tackle array-related challenges in competitive programming. Happy coding!