All Hard Articles

Python Program for N Queen Problem | Backtracking-3

The N Queen is the problem of placing N chess queens on an N×N chessboard so that no two queens attack each other. For example,… Read More

Python DSA-exercises

Python Programs

Python Program for Rabin-Karp Algorithm for Pattern Searching

Given a text txt[0..n-1] and a pattern pat[0..m-1], write a function search(char pat[], char txt[]) that prints all occurrences of pat[] in txt[]. You may… Read More

python searching-exercises

Python Programs

KMP Algorithm for Pattern Searching

Given a text txt[0 . . . N-1] and a pattern pat[0 . . . M-1], write a function search(char pat[], char txt[]) that prints… Read More

Accolite

Amazon

MakeMyTrip

MAQ Software

Oracle

Payu

DSA

Pattern Searching

Strings

Tournament Tree (Winner Tree) and Binary Heap

Given a team of N players. How many minimum games are required to find the second-best player? We can use adversary arguments based on… Read More

Advanced Data Structure

DSA

Heap

Program to count number of set bits in an (big) array

Given an integer array of length N (an arbitrarily large number). How to count number of set bits in the array?The simple approach would be, create an… Read More

Bit Magic

Divide and Conquer

DSA

Smallest window in a String containing all characters of other String

Given two strings, string, and pattern, the task is to find the smallest substring in string containing all characters of pattern. Examples: Input: string =… Read More

Amazon

Codenation

FactSet

MakeMyTrip

sliding-window

Streamoid Technologies

DSA

Hash

Strings

Data Structures and Algorithms | Set 26

Following questions have been asked in GATE 2011 exam. 1) A max-heap is a heap where the value of each parent is greater than or… Read More

GATE-CS-2011

GATE-CS-DS-&-Algo

GATE CS

MCQ

CRASH() macro – interpretation

Given below a small piece of code from an open source project, #ifndef __cplusplus typedef enum BoolenTag { false, true } bool; #endif… Read More

C-Macro & Preprocessor

C Language

C++

Next higher number with same number of set bits

Given a number x, find next number with same number of 1 bits in it’s binary representation.For example, consider x = 12, whose binary representation… Read More

Bit Magic

DSA

Structure Member Alignment, Padding and Data Packing

In C, the structures are used as data packs. They don’t provide any data encapsulation or data hiding features. In this article, we will discuss… Read More

C-Struct-Union-Enum

C Language

The OFFSETOF() macro

We know that the elements in a structure will be stored in sequential order of their declaration. How to extract the displacement of an element… Read More

C-Macro & Preprocessor

C Language

C++

Java Program for Merge Sort for Linked Lists

Merge sort is often preferred for sorting a linked list. The slow random-access performance of a linked list makes some other algorithms (such as quicksort)… Read More

Java Programs

Write one line functions for strcat() and strcmp()

Recursion can be used to do both tasks in one line. Below are one line implementations for stracat() and strcmp(). /* my_strcat(dest, src) copies data… Read More

C Array and String

C Language

Quine – A self-reproducing program

A quine is a program which prints a copy of its own as the only output. A quine takes no input. Quines are named after… Read More

C Language

C++

Inorder Tree Traversal without recursion and without stack!

Using Morris Traversal, we can traverse the tree without using stack and recursion. The idea of Morris Traversal is based on Threaded Binary Tree.… Read More

threaded-binary-tree

tree-traversal

DSA

Tree

Compute the integer absolute value (abs) without branching

We need not to do anything if a number is positive. We want to change only negative numbers. Since negative numbers are stored in 2’s… Read More

Bit Magic

DSA

Data Structures and Algorithms | Set 11

Following questions have been asked in GATE CS 2007 exam. 1. Consider a hash table of size seven, with starting index zero, and a hash… Read More

GATE-CS-2007

GATE-CS-DS-&-Algo

GATE CS

MCQ

C Program to Count Inversions in an array | Set 1 (Using Merge Sort)

Inversion Count for an array indicates – how far (or close) the array is from being sorted. If the array is already sorted, then the… Read More

C Programs

Data Structures and Algorithms | Set 8

Following questions have been asked in GATE CS exam. 1. Consider the following functions Which of the following is true? (GATE CS 2000) (a) h(n)… Read More

GATE-CS-2000

GATE-CS-2001

GATE-CS-DS-&-Algo

GATE CS

MCQ

C Program for Program for array rotation

Write a function rotate(arr[], d, n) that rotates arr[] of size n by d elements. Rotation of the above array by 2 will make array… Read More

C Programs