Rules for Solving a Coding Question in an Interview

Rules for Solving a Coding Question in an Interview


1 min read

  • If we are dealing with top/maximum/minimum/closest 'K' elements among 'N' elements, we will be using a Heap.

  • If the given input is a sorted array or a list, we will either be using Binary Search or the Two Pointers strategy.

  • If we need to try all combinations (or permutations) of the input, we can either use Backtracking or Breadth First Search.

  • Most of the questions related to Trees or Graphs can be solved either through Breadth First Search or Depth First Search.

  • Every recursive solution can be converted to an iterative solution using a stack.

  • For a problem involving arrays, if there exists a solution in O(n^2) time and O(1) space, there must exist two other solutions

    • Using a HashMap or Set for O(n) time and space.

    • Using sorting for O(n.log n) time O(1) space.

  • If a problem in asking for optimization(e.g. maximization or minimization), we will be using Dynamic Programming.

  • If we need to find some common substring among a set of strings, we will be using a HashMap or Trie.

  • If we need to search/manipulate a bunch of strings then Trie will be the best data structure.

  • If the problem is related to LinkedList and we can't use extra space, then use the Fast & Slow Pointer approach.