All Hard Articles

Inplace (Fixed space) M x N size matrix transpose

Given an M x N matrix, transpose the matrix without auxiliary memory.It is easy to transpose matrix using an auxiliary array. If the matrix is… Read More

DSA

Matrix

An in-place algorithm for String Transformation

Given a string, move all even positioned elements to the end of the string. While moving elements, keep the relative order of all even positioned… Read More

DSA

Strings

Construct BST from given preorder traversal using Stack

Given preorder traversal of a binary search tree, construct the BST.For example, if the given traversal is {10, 5, 1, 7, 40, 50}, then the… Read More

Amazon

Binary Search Tree

DSA

Stack

Tree

Print all permutations in sorted (lexicographic) order

Given a string, print all permutations of it in sorted order. For example, if the input string is “ABC”, then output should be “ABC, ACB,… Read More

lexicographic-ordering

permutation

Combinatorial

DSA

Mathematical

Strings

Construct Full Binary Tree from given preorder and postorder traversals

Given two arrays that represent preorder and postorder traversals of a full binary tree, construct the binary tree. Full Binary Tree is a binary tree… Read More

DSA

Tree

Find the element that appears once

Given an array where every element occurs three times, except one element which occurs only once. Find the element that occurs once. Note: Expected time… Read More

Amazon

Bitwise-XOR

Microsoft

Ola Cabs

Qualcomm

Arrays

Bit Magic

DSA

Mathematical

Microsoft Interview | Set 8

This about my experience of MS interview, which happened last day Division: Microsoft Bing R&D Rounds: Total 4 rounds (All face to face) Location: Hyderabad.… Read More

Microsoft

Experiences

Interview Experiences

Median of two Sorted Arrays of Different Sizes

Given two sorted arrays, a[] and b[], the task is to find the median of these sorted arrays, where N is the number of elements… Read More

Binary Search

median-finding

statistical-algorithms

Divide and Conquer

DSA

Searching

Find the k most frequent words from a file

Given a book of words. Assume you have enough main memory to accommodate all words. design a data structure to find top K maximum occurring… Read More

Advanced Data Structure

DSA

Searching

Amazon Interview | Set 6

Following are my interview details for senior software engineer in 2010. Thought of sharing it, if it helps anybody Telephonic Interview 1 1) Write your… Read More

Amazon

Experiences

Interview Experiences

Microsoft Interview | Set 5

Hi everyone, I would like to share my experience with MicroSoft, as i have been the lucky hire. Date: 27th August 2012 No. of Rounds:… Read More

Microsoft

Experiences

Interview Experiences

Given a number, find the next smallest palindrome

Given a number, find the next smallest palindrome larger than this number. For example, if the input number is “2 3 5 4 5”, the… Read More

Amazon

FactSet

MakeMyTrip

Microsoft

palindrome

Prime Number

Yahoo

Arrays

DSA

Mathematical

Sorting

Strings

Microsoft Interview | Set 3

I would like to thank GEEKSFORGEEKS team that they made my confidence level high when it comes to coding. I finished my interview today, hope… Read More

Microsoft

Experiences

Interview Experiences

Amazon Interview | Set 1

Please find the details of my amazon interviews below. Date of Interviews: 22nd August 2012 No of Rounds: 1 Written + 4 PI Type of Interviews: Campus… Read More

Amazon

Experiences

Interview Experiences

Word Wrap Problem

Given an array words[] of size n, where words[i] denotes the number of characters in one word. Let K be the limit on the number… Read More

Microsoft

DSA

Dynamic Programming

Struct Hack

What will be the size of following structure? CPP struct employee { int emp_id; int name_len; char name[0]; }; 4 + 4 + 0 =… Read More

C-Struct-Union-Enum

cpp-structure

C Language

const_cast in C++ | Type Casting operators

C++ supports following 4 types of casting operators: 1. const_cast 2. static_cast 3. dynamic_cast 4. reinterpret_cast 1. const_cast const_cast is used to cast away the… Read More

C Language

C++

DFA based division

Deterministic Finite Automaton (DFA) can be used to check whether a number “num” is divisible by “k” or not. If the number is not divisible,… Read More

divisibility

Microsoft

DSA

Mathematical

Find day of the week for a given date

Write a function that calculates the day of the week for any particular date in the past or future. A typical application is to calculate… Read More

date-time-program

Morgan Stanley

Samsung

DSA

Mathematical

Count numbers that don’t contain 3

Given a number n, write a function that returns count of numbers from 1 to n that don’t contain digit 3 in their decimal representation. Examples: … Read More

Basic Coding Problems

DSA

Mathematical