sorting

3Sum

Given an integer array, return all unique triplets where the sum is zero using two-pointer scanning with careful duplica…

3Sum Closest

Find the sum of three integers in an array that is closest to a given target using two-pointer scanning.

4Sum

The 4Sum problem requires finding all unique quadruplets in an array that sum to a specific target value.

Permutations II

Generate all unique permutations of an array containing duplicates using backtracking and pruning to avoid repeated sequ…

Group Anagrams

Group the anagrams in a list of strings using efficient hash table-based methods, focusing on array scanning.

Merge Intervals

Merge Intervals requires sorting an array of interval pairs and combining overlaps efficiently using sequential comparis…

Sort Colors

Sort Colors requires in-place reordering of an array using a two-pointer scanning strategy to group 0s, 1s, and 2s effic…

Merge Sorted Array

Merge two sorted arrays into the first array in non-decreasing order, using a two-pointer approach.

Insertion Sort List

Sort a singly linked list using insertion sort by carefully manipulating pointers to maintain a sorted order efficiently…

Sort List

Sort List requires sorting a singly linked list efficiently using pointer manipulation and merge sort for optimal perfor…

Maximum Gap

Find the largest difference between successive elements in a sorted array efficiently using linear time techniques and b…

Majority Element

Find the majority element in an array, where the element appears more than n/2 times, using efficient algorithms.

Largest Number

The problem asks to arrange integers to form the largest possible number, focusing on greedy algorithms and string handl…

Kth Largest Element in an Array

Find the kth largest element in an unsorted array using optimal approaches like Quickselect or heaps.

Contains Duplicate

Determine if an integer array contains any duplicate values by efficiently scanning with a hash lookup to ensure fast de…

Contains Duplicate III

The problem involves finding a pair of indices in an array where the index and value differences are within given limits…

Majority Element II

Identify all elements in an integer array appearing more than ⌊ n/3 ⌋ times using efficient array scanning and hash coun…

Valid Anagram

Check if two strings are anagrams using hashing or sorting techniques.

Missing Number

Find the missing number in an array containing distinct numbers in the range [0, n].

H-Index

Determine a researcher's h-index by analyzing citations using array sorting and counting techniques efficiently and accu…

Find Median from Data Stream

Implement a MedianFinder class that supports adding numbers and finding the median from a data stream.

Wiggle Sort II

Rearrange an array in a way that every odd-indexed element is greater than its adjacent even-indexed elements.

Top K Frequent Elements

Find the k most frequent elements from an array using efficient algorithms like hashing and sorting.

Intersection of Two Arrays

Find the intersection of two arrays while ensuring unique elements using efficient array scanning and hash lookups.