Placement preparation

Quadrilaterals: Types, Properties and Formulas

Six quadrilateral types: square, rectangle, parallelogram, rhombus, trapezium, and kite. Properties, area formulas, and worked examples for campus placement tests.

Count the Number of Ways to Reach the Nth Stair

Staircase problem solved four ways: naive recursion, memoized DP, tabulation, and O(1) space. Python code, verified Fibonacci values, and k-step variation.

Critical Reasoning for Placement Tests: A Beginner's Guide

Six question types, a 3-step approach, and four worked examples for critical reasoning in TCS NQT, AMCAT, CAT, and eLitmus.

11 May 2026 · 10 min read

Critical Reasoning Question Types for Placement Tests

Master the 6 critical reasoning question types tested in AMCAT, eLitmus, CoCubes, and company-specific placement tests, with worked examples and common traps.

Python Decorators: @syntax, functools.wraps, and Practical Examples

Learn Python decorators step by step: @decorator syntax, functools.wraps, parametrized decorators, class-based decorators, and placement interview examples.

eLitmus pH Test 2026: Exam Pattern, Negative Marking and Percentile

The eLitmus pH test: 60 questions across three sections in two hours. Negative marking rules, percentile calculation, and prep guide for 2026.

11 May 2026 · 9 min read

Modular Exponentiation in Python: pow(b, e, n) Explained

Compute b^e mod n without overflow using Python's three-argument pow(b, e, n) or the square-and-multiply algorithm. Worked example included.

Find All Ancestors of a Node in a Binary Tree

Find all ancestors of a node in a binary tree with recursive and iterative Python solutions. Includes complexity analysis and placement interview patterns.

Squares Near 10, 100 and 1000: The Base-Distance Trick

Square any number near 10, 100, or 1000 in two steps using (a+b)(a-b). Full derivations for 9², 98², 997², 1002², and placement practice problems.

Min and Max of Arithmetic Expression with + and * (Interval DP)

Find the minimum and maximum of a + and * expression by placing parentheses, using interval DP with a step-by-step worked example.

Shortest Path Between Two Vertices in an Undirected Graph

BFS-based shortest path in undirected graphs: adjacency-list representation, parent-tracking, path reconstruction, and Python + C++ code.

Squaring 2-Digit Numbers Ending in 1, 4, 5, and 6

Four shortcuts for squaring 2-digit numbers ending in 1, 4, 5, or 6, with worked examples, algebraic proof, and a reference table for placement aptitude.

Check if a Character is a Vowel or Consonant in C

Three C programs classify any character as a vowel, consonant, or non-alphabet input using if-else with tolower(), switch-case, and a strchr() lookup table.

Stress Interviews: Common Questions and How to Handle Them

A stress interview tests composure and clear thinking under pressure. Here's what to expect, which questions come up most often, and how to answer them.

Communication Skills for Campus Placements: GD, HR, and Beyond

GD rounds, HR interviews, and written assessments each test communication differently. Here's what engineering students need to practise and how.

Print All Distinct Elements in an Array in C

Three C programs to print all distinct elements in an array: nested-loop O(N²), sorting, and count-array, with complexity trade-offs and placement interview tips.

Technical Round Self-Study System: 2026 Engineer's Guide

A practical guide for building a self-study technical-round prep system covering DSA, OS, CN, DBMS, and programming: free and low-cost resources included.

Python Conditionals: if, if-else, elif, and Nested if Explained

Python's if, if-else, elif, and nested if statements control program flow. Syntax, worked examples, and truthiness edge cases for 0, '', [], and None.

4 Methods to Solve Linear Equations (With Worked Examples)

Substitution, elimination, cross-multiplication, and Cramer's rule explained with verified worked examples and placement-test strategy for engineering students.

C Command Line Arguments Set 2: 5 Placement Programs

Five C programs using argc/argv for placement interviews: sum of CLI args, even/odd count, string reverse, safe atoi parsing, and multi-arg processing.

Multithreading in Python: threading Module Complete Guide

Python multithreading with the threading module: create threads, use Lock, RLock, and Semaphore, understand the GIL, and pick the right concurrency tool.

Optimise Your LinkedIn Profile: Advanced 2026 Guide

Already have a LinkedIn profile? This advanced playbook covers SSI score, Boolean keyword placement, Creator mode, and ABM DM templates to drive recruiter inbound.

How to Prep for Product, Service, Analytics, and AI-First Companies

Product, service, analytics, and AI-first companies test very different skills. This guide maps what each bucket tests and how to split your prep time.

Probability Concepts and Problems for Aptitude Tests

How probability thinking works: sample space construction, addition and multiplication rules, conditional probability, and worked problems for placement aptitude tests.

Strong Number Program: Check in C, Python, and Java

Understand strong numbers (Krishnamurthy numbers), verify 145 and 40585 step by step, and write clean check programs in C, Python, and Java.

Check if a Graph is a Tree: Three Algorithms in Python

Three algorithms to check if an undirected graph is a tree: DFS with parent tracking, Union-Find, and edge-count plus BFS. Python code for each, O(V+E) analysis.

Count Common Subsequences of Two Strings

Count common subsequences of two strings using DP: derive the recurrence, trace a 4x4 table, implement in Python, and cut space to O(min(m,n)) with a rolling array.

Minimum Number of Jumps to Reach End of an Array

Greedy O(n) and DP O(n²) solutions for the minimum jumps problem, with worked examples verified from scratch and C, Python, Java programs.

11 May 2026 · 9 min read

Matrix Row and Column Sums: Find the Greatest

Find the sum of each row and column of a matrix, then identify which row and column has the greatest sum. Algorithm, C, Java, Python code, complexity.

Frequency of Each Array Element: 3 Approaches

Count how often each element appears in an array using nested loops, sorted sweep, and hash map. Python and C++ code with complexity analysis and edge cases.

Find Greatest of Two or Three Numbers: C, Python, and Java

If-else, ternary, and built-in approaches to finding the max of 2 or 3 numbers in C, Python, and Java, with N-numbers loop and edge cases.

Kth Maximum Element in a Binary Search Tree

Reverse inorder traversal finds the k-th maximum in a BST in O(H+k) time. Worked example with a 7-node tree, C++, Java, and Python code, plus edge cases.

Median of Two Sorted Arrays: Brute Force and Binary Search

Find the median of two sorted arrays using the merge approach and the O(log min(m,n)) binary search partition. Verified Python code included.

Saddle Point of a Matrix: C, C++, Java, and Python Programs

A saddle point is the minimum in its row and the maximum in its column. Learn the O(M×N) two-pass algorithm with working code in C, C++, Java, and Python.

Sum of Numbers in a Range: Naïve, Formula, Prefix Array

Three approaches to the range sum problem: O(n) loop, Gauss O(1) closed-form, and prefix-sum array for repeated queries. Verified examples in C, Java, and Python.

Program to Remove Spaces from a String: Python & C

Remove all whitespace from a string in Python and C: two-pointer, build-new-string, and library one-liners, with complexity analysis and edge cases.

Reverse Every Word in a Sentence: C, Java, Python

Two-pointer algorithm and code in C, Java, and Python to reverse every individual word in a sentence while keeping word order unchanged.

Python Command Line Arguments: sys.argv and argparse

Learn to read Python command line arguments with sys.argv and argparse. Covers basic usage, named flags, type conversion, and practical script patterns.

Python Inbuilt Looping Functions: A Complete Guide

Python's nine built-in iteration helpers: range, enumerate, zip, map, filter, sorted, reversed, iter, and next, with code examples for placement coding rounds.

Python Input: input(), Type Conversion, and Multiple Values

Learn how Python's input() function works, how to convert strings to int or float, read multiple values with split() and map(), and handle EOFError in placement tests.

Regular Expressions in Python: A Complete Guide

Python's re module: core syntax, API functions (search, findall, sub, split), compiled patterns, and real-world email and log examples for placement coding rounds.

Sort All Elements of a Matrix in Ascending Order

Sort every element of an M×N matrix in ascending order: flatten-sort-refill algorithm, worked 3×3 example, row-wise variant, and edge cases explained.

Spiral Matrix Printing: Print a 2D Matrix in Spiral Order

Print a 2D matrix in spiral order with the boundary-shrink approach. Python and Java solutions with traced examples for 3×3, 3×4, and edge cases.

Python operator Module: Operators as First-Class Functions

Python's operator module turns every built-in operator into a callable: add, mul, itemgetter, and more. Faster than lambdas in tight loops.

Squaring Numbers Ending in 5: The n(n+1) Shortcut

Square any number ending in 5 in seconds: multiply the prefix by the next integer, append 25. Full algebraic proof, 2-digit and 3-digit examples, aptitude practice.

10 Technical Interview and Aptitude Questions: Set 6 (Solved)

Solved Set 6: arrays vs lists, OOP pillars, macros vs functions, Floyd's cycle detection, and swap-without-temp in C, ten questions campus drives test.

From Campus to Corporate: 10 Things Engineering Graduates Should Know

Your first IT job in India changes more than your schedule. Here are 10 things every engineering fresher should know before Day 1 at TCS, Infosys, or a product company.

Python Arrays: Operations, Patterns, and Placement Tips (2026)

Learn Python arrays with the array module, lists vs arrays, common operations, time complexity, and classic placement patterns like rotation and two-sum.