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DSA

20.2K+ posts

Last Updated: 28 July 2025

In programming, prefix sum arrays are a simple and powerful technique. They make it easier to solve problems that involve finding the sum of numbers between two points in ...read more

DSA

Range-Based Count of X in Sorted Array

Last Updated: 01 August 2025

Given a sorted array arr[] and a list of queries represented as a 2D array queries[][]. Each query is a triplet of the form [l, r, x], where l and r are indices in the arr...read more

DSA

Count Frequency of an Element in a Given Range

Last Updated: 16 July 2025

Given an array arr[] of integers and a 2D array queries[][], where each queries[i] contains three integers: l, r, and x. For each query, determine how many times the eleme...read more

DSA

Binary Search

Maximum Non-Overlapping Odd Palindrome Sum

Last Updated: 31 July 2025

Given a string s consisting of lowercase English letters, find the maximum possible sum of the lengths of any two non-empty and non-overlapping palindromic substrings of o...read more

DSA

strings

Tywin's War Strategy

Last Updated: 18 July 2025

Given an array arr[] of length n, where arr[i] is the number of soldiers in the i-th troop, and an integer k. A troop is called lucky if its soldier count is a multiple of...read more

DSA

Minimize Difference

Last Updated: 24 July 2025

Given an array arr[] of strings, where each string represents a time in 24-hour format ("HH:MM:SS"), find the minimum absolute difference in seconds between any two time v...read more

DSA

strings

Longest Periodic Proper Prefix

Last Updated: 04 August 2025

Given a string s, find the length of the longest proper prefix such that repeating this prefix one or more times forms a string that contains s as a prefix. If no such pre...read more

DSA

Balance Consonant and Vowels Ratio

Last Updated: 11 July 2025

You are given an array of strings arr[], where each string contains only lowercase English letters. Count the number of contiguous subarrays (i.e., one or more consecutive...read more

DSA

Powerful Integers

Last Updated: 05 July 2025

You are given a 2D integer array intervals[][] of length n and integer k, where each intervals[i] = [start, end] represents a closed interval (i.e., all integers from star...read more

Last Updated: 28 July 2025

Given a string s consisting of lowercase English letters, identify all characters whose first and last occurrences are at different positions.For each such character, comp...read more

Local Min and Max Sequence Ordering

Last Updated: 23 July 2025

Given an integer array arr[] representing a sequence of elevations, Return an array that includes:The first and last elements of the array.Every element where the trend of...read more

DSA

Counting Even-Frequency Characters in a String

Last Updated: 26 July 2025

Given a string s consist of lowercase english letters, count how many distinct characters appear an even number of times.Examples: Input: s = "abacaba"Output: 2Explanation...read more

DSA

Candidates with majority vote

Last Updated: 27 July 2025

Given an array arr[] of positive integers where each element represents a vote for a candidate, Find all candidates who receive more than ⌊n/3⌋ of the total votes. The res...read more

DSA

Floor and Ceil of Integer Division

Last Updated: 14 July 2025

Given two integers a and b (where b ≠ 0). The objective is to find:• The floor of the division a / b, denoted as ⌊a / b⌋ — the greatest integer less than or equal to a / b...read more

DSA

Maths

Must‑Have Digit

Last Updated: 14 July 2025

Given an integernrepresenting the number of digits, and an arrayarr[] of digits (0–9), count how many n‑digit positive integers can be formed such that at least one digit ...read more

DSA

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