enumeration

Count Primes

Count all prime numbers less than a given integer n using efficient array and math-based enumeration techniques.

Largest Palindrome Product

Find the largest palindromic number from the product of two n-digit integers using math and enumeration efficiently.

Ambiguous Coordinates

Find all valid 2D coordinate possibilities for an ambiguous input string using backtracking and pruning techniques.

Consecutive Numbers Sum

Find the number of ways to express a number as the sum of consecutive positive integers.

Longest Mountain in Array

Find the length of the longest subarray forming a mountain pattern using state transitions and two-pointer logic efficie…

Reordered Power of 2

Determine if a number's digits can be rearranged to form a power of two using counting and hash-based checks.

Super Palindromes

Count all super-palindromes in a given numeric range, where each is a palindrome and square of a palindrome.

Largest Time for Given Digits

Given four digits, determine the latest valid 24-hour time possible using each digit exactly once with backtracking.

Powerful Integers

Find all integers that can be expressed as x^i + y^j up to a given bound using a Hash Table plus Math approach.

Sequential Digits

Find all integers within a range whose digits form a strictly increasing consecutive sequence using enumeration techniqu…

Count Good Triplets

Count Good Triplets requires identifying all triplets in an array that satisfy multiple absolute difference constraints …

Detect Pattern of Length M Repeated K or More Times

Determine if a subarray of length m repeats k or more consecutive times in a given integer array efficiently.

Maximum Number of Achievable Transfer Requests

Find the maximum number of achievable transfer requests between buildings with constraints on net employee transfers.

Count Subtrees With Max Distance Between Cities

This problem asks you to count subtrees in a tree structure where the maximum distance between any two cities matches sp…

Coordinate With Maximum Network Quality

Determine the coordinate with the maximum network quality by summing signal strengths from all reachable towers efficien…

Lexicographically Smallest String After Applying Operations

Optimize a string through rotations and additions to get the lexicographically smallest possible result using string man…

Count Substrings That Differ by One Character

Count all substrings from s that differ by exactly one character from some substring in t using precise substring compar…

Minimum Degree of a Connected Trio in a Graph

Find the minimum degree of a connected trio in a graph using enumeration over nodes and edges.

Splitting a String Into Descending Consecutive Values

Check if a string of digits can be split into descending consecutive values where the difference between them is 1.

Sum of All Subset XOR Totals

Compute the sum of all subset XOR totals using a backtracking search with pruning for arrays of small size.

Count Square Sum Triples

Count Square Sum Triples asks to find the number of integer triples where a² + b² = c² for values between 1 and n.

Three Divisors

Determine if a given integer has exactly three positive divisors.

Check if Move is Legal

Determine if a move on an 8x8 board is legal by validating lines in all directions using array and matrix patterns.

Count Special Quadruplets

Count Special Quadruplets requires scanning arrays and using hash lookups to efficiently find quadruplets matching sum c…