become a recursion pro

1. BECOME A Recursion Pro IN JUST 10 DAYS

2. The final pages contains Pro tips for mastering recursion. Do check it out before practicing these problems Curated by

3. Day 1 Question 1 Print 1 to n without using loop You are given an integer N. Print numbers from 1 to N without the help of loops. Example Input: N = 5 Output: 1 2 3 4 5 Explanation: We have to print numbers from 1 to 5. Practice Question Asked in: Tutort Provides 1:1 Mentorship from Industry experts Curated by

4. Day 2 Question 2 Fibonacci Number The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is, F(0)= 0, F(1)=1 F(n)= F(n-1) + F(n-2), for n>1 Given n, calculate F(n). Example Input: n = 2
 Output: 1
 Explanation: F(2) = F(1) + F(0) = 1 + 0 = 1. Practice Question Asked in: Curated by

5. Day 2 Question 3 Sum of digits Given a number, N. Find the sum of all the digits of N Example Input: N = 12 Output: 3 Explanation: Sum of 12's digits: 1 + 2 = 3 Practice Question Asked in: From From To To Success Story Story Success Ashish Joshi Ashish Joshi Curated by

6. Question 4 Palindrome String Given a string S, check if it is palindrome or not. Example Input:S = "abba" Output: 1 Explanation: S is a palindrome Practice Question Asked in: Question 5 Power of Two Given an integer n, return true if it is a power of two otherwise return false. An integer n is a power of two, if there exists an integer x such that n == 2x Example Input: n = 1
 Output: true
 Explanation: 20 = 1 Practice Question Asked in: Curated by

7. Day 3 Question 6 Rope Cutting You are given N ropes. A cut operation is performed on ropes such that all of them are reduced by the length of the smallest rope. Display the number of ropes left after every cut operation until the length of each rope is zero. Example Input : arr[ ] = {5, 1, 1, 2, 3, 5} Output : 4 3 2 Explanation: In the first operation, the minimum ropes are 1 So, we reduce length 1 from all of them after reducing we left with 4 ropes and we do the same for rest. Practice Question Asked in: Tutort Provides Dedicated Placement Team Curated by

8. Question 7 Valid Parentheses Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: 1. Open brackets must be closed by the same type of brackets. 2. Open brackets must be closed in the correct order. 3. Every close bracket has a corresponding open bracket of the same type. Example Input: s = "()"
 Output: true Practice From From To To Success Story Story Success Akansha Likhdhari Akansha Likhdhari Curated by

9. Day 3 Question 8 Pow(x, n) Implement pow(x, n), which calculates x raised to the power n (i.e., x ) n Example Input: x = 2.00000, n = 10
 Output: 1024.00000 Practice 1250+ 350+ 2.1CR Career Transitions Hiring Partners Highest CTC One of the best institutes for getting started with DSA and System Design. It also assisted me in launching my technical career and in honing my problem-solving and coding abilities. I was placed in more than 6+ product based companies because of their constant support. Placed at Avishkar Dalvi Curated by Curated by

10. Day 4 Subsets Given a set of positive integers, find all its subsets. Example Input : array = {1, 2, 3} Output : // this space denotes null element. 1 1 2 1 2 3 1 3 2 2 3 3 Explanation: The following are the subsets of the array {1, 2, 3}. Practice Asked in: Curated by Curated by

11. Day 5 Subset Sum Problem Given an array of non-negative integers, and a value sum, determine if there is a subset of the given set with sum equal to given sum. Example Input: N = 6 arr[] = {3, 34, 4, 12, 5, 2} sum = 9 Output: 1 Explanation: Here there exists a subset with sum = 9, 4+3+2 = 9. Asked in: Practice Curated by Curated by

12. Day 5 Question 11 Letter Combinations of a Phone Number Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. Example Input: digits = "23"
 Output: ["ad","ae","af","bd","be","bf","cd","ce","cf"] Asked in: Practice Why Tutort Academy? 350+ 2.1CR 1250+ Hiring Partners Highest CTC Career Transitions I really want to thank Tutort Academy from bottom of my heart for helping me brushing up system design, data structures and algorithms for the Google interview preparation. Akash Shrivastava Curated by Curated by

13. Day 6 Question 12 Tower of Hanoi The tower of Hanoi is a famous puzzle where we have three rods and N disks. The objective of the puzzle is to move the entire stack to another rod. You are given the number of discs N. Initially, these discs are in the rod 1. You need to print all the steps of discs movement so that all the discs reach the 3rd rod. Also, you need to find the total moves. Note: The discs are arranged such that the top disc is numbered 1 and the bottom-most disc is numbered N. Also, all the discs have different sizes and a bigger disc cannot be put on the top of a smaller disc. Refer the provided link to get a better clarity about the puzzle. Example Input: N = 2 Output: move disk 1 from rod 1 to rod 2 move disk 2 from rod 1 to rod 3 move disk 1 from rod 2 to rod 3 3 Explanation: For N=2 , steps will be as follows in the example and total 3 steps will be taken. Practice Asked in: Curated by Curated by

14. Day 6 Question 13 Josephus Problem Given the total number of persons n and a number k which indicates that k-1 persons are skipped and kth person is killed in circle in a fixed direction. After each operation, the count will start from k+1th person. The task is to choose the safe place in the circle so that when you perform these operations starting from 1st place in the circle, you are the last one remaining and survive.starting from 1st place in the circle, you are the last one remaining and survive. Example Input: n = 3 k = 2 Output: 3 Explanation: There are 3 persons so skipping 1 person i.e 1st person 2nd person will be killed. Thus the safe position is 3. Asked in: Practice Curated by Curated by

15. Day 7 Question 14 Find all possible palindromic partitions of a String Given a String S, Find all possible Palindromic partitions of the given String. Example Input: S = "geeks" Output: g e e k s g ee k s Explanation: All possible palindromic partitions are printed. Asked in: Practice Curated by Curated by

16. Day 8 Expression Add Operators Given a string S that contains only digits (0-9) and an integer target, return all possible strings to insert the binary operator ' + ', ' - ', or ' * ' between the digits of S so that the resultant expression evaluates to the target value Note: 1. Operands in the returned expressions should not contain leading zeros. For example, 2 + 03 is not allowed whereas 20 + 3 is fine. It is allowed to not insert any of the operators. 2 If no solution is found, return an empty string array Example Input: S = "123"target = 6 Output: { "1*2*3", "1+2+3"} Explanation: Both "1*2*3" and "1+2+3" evaluate to 6. Asked in: Practice Curated by Curated by

17. Day 9 Question 16 Reverse Nodes in k-Group Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. k is a positive integer and is less than or equal to the length of the linked list. If the number of nodes is not a multiple of k then left-out nodes, in the end, should remain as it is. You may not alter the values in the list's nodes, only nodes themselves may be changed. Example Practice Asked in: Curated by Curated by

18. Day 10 Question 17 N-Queens The n-queens puzzle is the problem of placing n queens on an n x n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n- queens puzzle. You may return the answer in any order. Each solution contains a distinct board configuration of the n-queens' placement, where 'Q' and '.' both indicate a queen and an empty space, respectively. Example Input: n = 4
 Output: [[".Q..","...Q","Q...","..Q."], ["..Q.","Q...","...Q",".Q.."]] 
 Explanation: There exist two distinct solutions to the 4-queens puzzle as shown Asked in: Practice Curated by Curated by

19. Question 18 Scrambled String Given two strings S1 and S2 of equal length, the task is to determine if S2 is a scrambled form of S1. Scrambled string: Given string str, we can represent it as a binary tree by partitioning it into two non-empty substrings recursively. To scramble the string, we may choose any non-leaf node and swap its two children. Suppose, we choose the node co and swap its two children, it produces a scrambled string ocder. Similarly, if we continue to swap the children of nodes der and er, it produces a scrambled string ocred. Note: Scrambled string is not the same as an Anagram. Print "Yes" if S2 is a scrambled form of S1 otherwise print "No". Curated by Curated by

20. Question 18 Scrambled String Example Asked in: Practice Curated by Curated by

21. Here are some tips to help you become proficient in using recursion: Clear Out Your Basics: Start with a solid understanding of recursion and how it works, understand how a function calls itself to solve a problem in smaller, similar instances. 01 Identify Base Cases: Every recursive function should have one or more base cases, which are the simplest scenarios that can be solved directly, it’s Important to prevent infinite recursion. 02 Create the Recursive Case: For non-base cases, define how the problem can be broken down into smaller, similar subproblems. This is the recursive case, and it should eventually lead to the base case. 03 Visualize Recursion: Use visualization techniques, such as recursion trees or stack diagrams, to understand the flow of recursive function calls and how they build up and resolve. 04 Test and Debug: Test your recursive functions with various inputs to ensure they work correctly. Be prepared for stack overflow errors in case of incorrect base cases or excessive recursion. 05 Curated by Curated by

22. Maintain State: Ensure that the state of your program is maintained correctly across recursive calls. This includes variables, data structures, and other information necessary to solve the problem. 06 Use Helper Functions: In some cases, it may be helpful to create a helper function within your recursive function to encapsulate the recursion logic and pass additional parameters if needed. 07 Practice, Practice, Practice: Recursion can be challenging, so practice is essential. Work on a variety of problems that can be solved using recursion to gain experience and confidence. 08 Learn from Examples: Study and understand examples of recursive algorithms and functions, such as those for calculating factorials, Fibonacci sequences, or traversing data structures like trees and graphs. Read advanced data structures and algorithms, such as merge sort, quicksort, and tree traversal, rely on recursion. 09 Avoid Excessive Recursion: 10 While recursion is elegant, it may not always be the most efficient solution. In some cases, iterative approaches may be better for performance reasons. Curated by Curated by

23. Start Your Upskilling with us Explore our courses Data Structures and Algorithms
 with System Design Full Stack Specialisation
 In Software Development www.tutort.net Read more on Quora Watch us on Youtube Follow us on