Anagram Checker Plus
MediumGiven two strings, determine if they are anagrams of each other. Additionally, find the minimum number of character dele...
Cipher Cascade
EasyEncrypt a string using a dynamic Caesar cipher where each character is shifted by its position index (0-based). For exam...
Most Common Subsequence
MediumGiven two strings, find the longest common subsequence (LCS). A subsequence is derived by deleting some characters witho...
Square-Free Sequence
MediumGenerate the first N square-free numbers. A square-free number is a positive integer that is not divisible by any perfec...
Reverse Factorial
EasyGiven a positive integer, determine if it is a factorial of some integer. If yes, return that integer; if no, return -1....
Digit Product Chain
EasyStarting from a given number, repeatedly multiply all its digits until you get a single-digit result. Count how many mul...
Lucky Triples
MediumGiven an array of positive integers, count the number of triples (i, j, k) where i < j < k and A[i] × A[j] = A[k]. These...
Binary Palindrome Sum
MediumFind the sum of all positive integers ≤ N whose binary representation (without leading zeros) is a palindrome. A palindr...
Undo Stack Simulation
MediumSimulate a text editor that supports three operations: TYPE (add text), UNDO (reverse last operation), and REDO (restore...
Rotating Queue
MediumGiven a circular queue and a sequence of target elements, find the minimum number of rotations needed to bring each targ...