100+ SDE & SDET Interview Questions With Answers

SDE/SDET Interview questions that will ramp up your interview preparation

Myself, Balaji Boggaram Ramanarayan – I bag experience in taking/preparing for interviews in several big companies and always felt sharing a few of them such that it might be useful for you in interview preparation.

Note: These questions might help you ramp up your speed in the path of preparing for SDE /SDET interviews in most techie companies. 

 SDE – Software Development Engineer
 SDET – Software Development Engineer in Test 

The must-know SDE/SDET Interview Questions

1. Heap – Max Heaps and Min Heaps
2. Conversions: Decimal, Binary, Hex, Octal (All other possible combinations)
3. 90 Degrees Matrix conversion
4. Quick Sort + Applications
5. Merge Sort + Applications
6. Remove duplicates in a String — In place
7. Reverse a string – Inplace
8. Decide if 2 strings are anagrams or not?
9. Binary Search
10. Reverse SLL without using any extra nodes
11. Maximum Subarray [Kadane Algorithm]
12. Find an element that is repeated more than n/2 times in a given set/array. [Moores Voting algorithm]
13. Find an element in rotated Binary sorted array
14. Implement power function without pow() function
15.  Verify if the given linked list is circular/cyclic or Acyclic. Follow up can be to indicate the starting point of the cycle
16. Implement Blocking queue
17. Find a pair in an array that will sum up to a particular number
18. Reverse a double linked list
19. Reverse pairs in SLL. i.e I/P : a->b->c->d->e->f O/p : b->a->d->c->f->e
20. Segregate even and odd nodes in a given linked list
21. Addition of 2 linked lists to separate one. (also learn inplace)
22. Convert SLL into DLL (XOR based linked lists)
23. Circular shift an array of integer input array by ‘k’ number of elements
24. Search for a given pattern in the text [Rabin Karp Algorithm]
25. atio() and itoa() implementations (ASCII to integer and Integer to ASCII)
26.  Binary Semaphores
27. Generate subsets of a given set of integers
28. Generate all permutations of a given string
29. Level order Traversal
30. The inorder successor of a given node in BST (Binary Search Tree)

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SDE/SDET Interview Questions- you should be able to answer

1. Find ‘k’ largest /smallest elements in a given array (Hint: can use heaps)
2. Heap Sort + applications
3. Find minimum length unsorted subarray on which storing them makes a complete sorted array
4. Search if a given pattern exists in input text using Suffix Arrays
5. Re-arrange a string so that all same characters are ‘d’ distant apart
6. Knights tour problem
7. Rat in Maze [Back tracking]
8. Find out if two rectangles overlap or not
9. Where are the closest pair of points in the given plane
10. Find all subset of elements in the given set whose sum equals to a given target
11. Compute x^y such that it can work for floats and negative values
12. Find median of  given two input sorted arrays
13. Find the total no of zeros in a given array of 1’s followed by 0’s
14. If there is any sub-array find the ones which sum up to zero
15. Count number of inversions in a given array
16. Find a minimum element in a rotated sorted array
17. Which is the fixed point in the given array
18. Find the maximum subarray sum [D&C]
19. Count # of occurrences of a number in the sorted array
20. Find the max and min element in a given array with a minimal number of comparisons

30+ Software Developer (SDE) / Software Developer In Test (SDET) Questions for you

1. Check if a number is multiple of 3 or not?
2. One line function to check if a number is the power of 2 or not?
3. Function to multiple a number by 7.
4. Which is the function to multiply two numbers without using * product operator
5. Function to write Fibonacci series in an iterative manner
6. Generate all prime numbers less than or equal to n [Sieve of Erastho..]
7. Given a number, Find the next biggest palindrome number
8. Implement logic for a fair coin from a biased coin
9.  Check if a number is divisible by 7 without mod operator
10. Find all the possible words from a phone keypad
11. Lexicographic sort of permutation of all words
12. Shuffle a given array/deck of cards [Fisher Yates Algo]
13. Reservoir Sampling Algorithm
14. Select ‘k’ random elements from ‘n’ elements
15. Given a number ‘n’. generate a pascal triangle out of it.
16. Write an exponential precision function [Taylor series]
17. Generate all prime factors of a given number
18. Generate all possible combinations of ‘r’ elements in a given array of size ‘n’ [Probability Distribution Function]
19. Length of Longest common subsequence of a given sequence of numbers
20. Find minimum cost path in a given cost matrix
21. Total # of solutions in a coin change problem
22. Find binomial co-efficient
23. Knap-sack standard problem
24. Egg-Drop standard problem
25. Length of longest palindrome sequence
26. Palindrome Partitioning
27. Maximum Length of chained increasing pair
28. Find the middle of the given linked list
29. Check if a given Single linked list is a palindrome or not
30. Insert/Delete/Search in max heap
31. Implement sizeof() operator
32. Find successor of given BST
33. Locate all triangle triples in the given array
34. Find the lowest common ancestor of a given node
35. Return a single element by knocking out all other elements by ‘k’ [Josephus]

Find more Software Developer (SDE) / Software Developer In Test (SDET) Questions

1. Given a sorted skewed binary tree, Create a BST out of it.
2. Given an array with integers, Output all the elements which were repeated exactly twice
3. Maximum depth/height/diameter of a given tree
4. Serialize and Deserialize a given binary tree
5. Find a single repeated or non-repeated number in the conditional list. (XOR)
6. Implement “diff” in Linux
7. Program to count # of set bits in a given integer.
8. Convert BST to a doubly-linked list
9. Convert integer to String without.toString()
10. GCD of two numerals
11. Given an array in post-order traversal, check whether the given array is in BST or not
12. Reverse the words in a given English sentence
13. Get the median of a stream of large numbers
14. Print all the paths of a given Binary Tree from root to leaf
15. Modify array such that arr[i] == arr[arr[i]] Inplace
16. Find the missing number in a billion number list
17. Bitwise addition

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