Recursion and Divide & Conquer Approach

Using a recursive algorithm, certain problems can be solved quite easily. Key Ideas to understand in recursion

Different ideas of Recursive solutions
Correctness and Base Cases
Stack Overflow Scenario
Iteration Vs Recursion
Analysis of recursion using Recursion Tree Method and Master Theorem

Divide-and-Conquer approach : It Breaks a problem into subproblems that are similar to the original problem, recursively solves the subproblems, and finally combines the solutions to the subproblems to solve the original problem. This method usually allows us to reduce the time complexity to a large extent.

We use a recursive approach during the solution of the problem using Divide and Conquer, Dynamic Programing and Backtracking. We also solve several arrays, tree, linked list, string and graph-related Interview problems using recursion.
Important Recursive Algorithms: Binary Search, Merge Sort and Quick Sort. There are several commonly asked interview questions that use the idea of binary search.

#	Title	Difficulty	Companies
1 .	Recursion : Recursive Solutions, Base Case and Recursion Call stack
2 .	Example 1 : Find nth Factorial	Easy
3 .	Example 2 : Recursive Insertion Sort	Medium
4 .	Comparison : Iteration vs Recursion
5 .	Divide and Conquer approach
6 .	Example 1 : Binary Search	Easy
7 .	Example 2 : Search a 2-D Matrix	Medium	Amazon Microsoft
8 .	Example 3 : Merge Sort	Hard	Google Amazon Intel
9 .	Example 4 : Quick Sort	Hard	Microsoft Google Goldman Sachs
10 .	Example 5: Missing Number	Easy	Amazon Yahoo
11 .	Example 6 : Search in a sorted and infinite array	Hard	Amazon
12 .	Analysis of Recursion : Recursion Tree Method and Master Theorem
13 .	Comparison : Sorting Algorithms

Title

Solution

Difficulty

Companies