Placement prep + AI for engineers

Nested Loops in Python: Types, Syntax, and Examples

Four types of nested loops in Python with working code and placement-round examples. Covers for, while, mixed variants, and break/continue control.

Opening and Closing Gates Problem: Wipro Coding Walkthrough

The opening and closing gates problem is a Wipro coding round question based on balanced parentheses. Algorithm, worked solution, and test cases all in one place.

Operator Overloading in Python: Magic Methods with Examples

How Python maps +, -, == and other operators to dunder methods like __add__ and __lt__. Covers the full magic-method table plus two worked placement-style examples.

Parallel Structure in Sentence Correction: 5 Error Types

Five parallel-structure error types in placement verbal tests, with one fix rule each. Worked examples for AMCAT, TCS NQT, and Cocubes sentence correction.

Persistent Systems Placement Papers 2026: Test Pattern and Solutions

Persistent Systems' 60-question online test covers technical CS and aptitude. Full 2026 test pattern, section syllabus, and verified worked sample questions.

Persistent Systems Recruitment Process: 2026 Guide

Four-section online test, technical round, and HR interview at Persistent Systems, complete 2026 syllabus breakdown and prep strategy for freshers.

Philips Selection Process 2026: Rounds, Eligibility and Prep

Step-by-step breakdown of Philips's fresher recruitment process: online aptitude test, technical interview, and HR round, with eligibility criteria and prep tips.

A 6-Week Placement Training Plan for Engineering Freshers

Structure your placement training around the TCS NQT pattern, aptitude topics, coding fundamentals, and mock tests to reach campus drive day prepared.

English Prepositions of Time: at, on, in, by, for and since

Master English prepositions of time with clear rules for at, on, in, by, for, since and until. Includes common error corrections and placement test practice questions.

Prepositions in Sentence Correction: Error Types and Fix Rules

Four preposition error types tested in placement aptitude tests, each with worked examples: wrong preposition, missing, redundant, and idiomatic phrases.

Python Program to Print Prime Numbers in a Range

Step-by-step Python programs to print prime numbers in a range. Covers trial division, Python's for/else idiom, and the Sieve of Eratosthenes.

Armstrong Numbers in a Range: C, C++, Java, Python

Programs to print Armstrong numbers between two intervals in C, C++, Java, Python. Traced algorithm, integer-power fix, and time complexity.

Print an Array in Zigzag Order in Python

Step-by-step guide to rearranging a Python list in zigzag order. Covers the O(n) swap algorithm, traced examples, edge cases, and CRT placement patterns.

Printing Variables in Python: Single, Multiple, Formatted

Four Python 3 methods to print variables with text: commas, % operator, .format(), and f-strings. Includes working code, common error fixes, and a comparison table.

Program to Add Two Matrices in C, Java, and Python

How to add two matrices in C, Java, and Python: algorithm, worked example, O(m×n) time and space complexity, and common placement coding test mistakes.

Check if Two Arrays Are Equal: 3 Approaches Explained

Three approaches to check if two arrays are equal: sort-and-compare, frequency count, and direct match, with working code and complexity analysis.

Abundant Number Program: C, Java and Python with √n Check

An abundant number has a proper-divisor sum greater than itself. Code in C, Java, and Python using the O(√n) loop, with worked examples for 12, 18, and 20.

Count Edges in an Undirected Graph: Algorithm and Code

Learn how to count edges in an undirected graph using the Handshaking Lemma. Step-by-step algorithm, Python and C++ code, and complexity analysis included.

Count Even and Odd Elements in an Array

Single-pass O(n) algorithm to count even and odd elements in an array. Working code in C, C++, Python, and Java, with complexity analysis and edge cases.

Count Vowels, Consonants, Digits and Special Characters in a String

Programs in Python, C, and Java to count vowels, consonants, digits, and special characters in a string. Algorithm, code, and traced outputs included.

Find All 0(1+)0 Patterns in a String: C & Python Guide

Count every 0(1+)0 occurrence in a binary string using a linear scan. C and Python code included, plus edge cases and O(n) complexity explained for placement rounds.

Lower Triangular Matrix Check: Programs in C, Java, Python

A square matrix is lower triangular when all entries above the main diagonal are zero. Programs in C, C++, Java, and Python with traced example and complexity analysis.

Check if a Matrix Is Upper Triangular: Code and Complexity

Verify whether a square matrix is upper triangular: the below-diagonal condition, verified C, Python, and Java code, and O(n²) complexity analysis for placement rounds.

Kth Smallest Element in an Unsorted Array: 4 C++ Approaches

Four C++ methods to find the Kth smallest element in an unsorted array: sort, QuickSelect, max-heap, and nth_element, with complexity trade-offs and placement tips.

Find Duplicate Elements in an Array: 5 Approaches

Five approaches to find duplicates in an array: O(n²) nested loops, sort-and-scan, hash set, XOR trick, and Floyd's cycle detection, with C, C++, and Python code.

ASCII Value of a Character: C, C++, Java, Python

Programs to find the ASCII value of a character in C, C++, Java, and Python. Key ASCII ranges, worked examples, and interview variants for placement tests.

The Handshakes Problem: Formula, Derivation, and Code

Derive the handshakes formula step by step, verify worked examples, and implement the solution in Python and C. A combinatorics guide for placement aptitude rounds.

Maximum Product Subarray: Algorithm, Code, and Dry Run

Find the maximum product subarray using the max-min tracking method. Algorithm steps, dry run table, Python and C code, complexity analysis, and placement context.

Maximum Scalar Product of Two Vectors: Algorithm and Code

Find the maximum scalar product of two vectors by sorting both arrays in the same order. Algorithm, complexity analysis, and verified C and Python code.

Find Min and Max in Each Row of a Matrix

C and Python programs to find minimum and maximum elements in each row of a matrix. Includes algorithm, complexity analysis, and placement test variations.

Program to Find Minimum Scalar Product of Two Vectors

Find the minimum dot product of two integer arrays by sorting one ascending and the other descending. Algorithm, proof, worked example, and C/C++/Java/Python code.

Days in a Given Month: Python, Java, C and C++ Programs

Python, Java, C, and C++ programs to find days in a given month and year. Covers the leap year rule, if-elif, array lookup, and standard library approaches.

Find the Quadrant of Given Coordinates: C Program and Explanation

Find the quadrant of any coordinate pair using a C program. Covers all four quadrants, origin, x-axis and y-axis cases, and O(1) complexity analysis.

Sum of All Numbers in a String: 4 Language Solutions

Step-by-step programs in Python, Java, C, and C++ to extract every number from a string and return their sum, with worked examples and complexity notes.

Sum of Array Elements: C, C++, Java, and Python

Find the sum of elements in a given array using loop-based programs and built-in functions in C, C++, Java, and Python, with examples and complexity analysis.

Sum of Perfect Square Elements in Array: C, C++, Java, Python

Find the sum of perfect square elements in an array in C, C++, Java, and Python. Algorithm, floating-point safety, traced example, and complexity analysis.

Sum of Boundary Elements of a Matrix: C, C++, Java, Python

Two complete approaches: O(N+M) optimised and O(N×M) check-each, to find the sum of boundary elements of a matrix, in C, C++, Java, and Python.

Program to Remove All Non-Alphabet Characters from a String

Step-by-step algorithm and verified C, C++, Java, and Python code to remove all non-alphabet characters from a string, with edge cases and O(n) complexity analysis.

Remove Duplicate Elements from an Array: Python, C++, Java

Remove array duplicates: two-pointer for sorted arrays (O(n), O(1) space); HashSet for unsorted (O(n), O(n) space). Code in Python, C++, and Java.

Program to Replace a Substring in a String

Manual algorithm plus working code in Python, Java, and C to replace every occurrence of a substring, with Wipro placement context and edge cases.

Find Nth Node from End of a Linked List: Two Approaches

Two methods to return the Nth node from the end of a linked list: the length-based two-pass approach and the single-pass two-pointer technique.

Reverse a Number in C, C++, Java and Python

Iterative and recursive approaches to reverse a number in C, C++, Java, and Python. Step-by-step trace, working code, and complexity analysis.

Reverse an Array: 4 Methods in C, Python, and Java

Four methods to reverse an array: print-from-end, auxiliary array, in-place swap, and recursion. Working code in C, Python, and Java with complexity analysis.

Swap Two Numbers Without a Third Variable

Three ways to swap two numbers without a third variable, with C code: arithmetic, XOR, and multiply-divide. Covers trade-offs, overflow risk, and what interviewers ask.

Pronoun-Antecedent Agreement: Sentence Correction Rules

Five pronoun-antecedent agreement error types tested in AMCAT, TCS NQT, and placement verbal sections. Rules, worked examples, and practice questions.

Function Prototype in C: Declaration, Syntax, and Why It Matters

A function prototype tells the C compiler the return type, argument count, and argument types before the function is defined. Learn what happens when you skip it.

Pyramid Pattern Programs Using Numbers: C, Python, Java

C, C++, Java, and Python code for seven number-pyramid variants, including Floyd's triangle and Pascal's triangle, with verified output for height 5.

9 May 2026 · 12 min read