Sorting

Remove duplicates from sorted array in-place, return new length

Return squares of sorted array in sorted order (handles negatives)

Find all unique triplets that sum to zero

Sort array of 0s, 1s, 2s in-place using three pointers

Merge two sorted arrays into first array in-place

Minimum boats to carry people with weight limit

Find all unique quadruplets that sum to target

Find intersection of two arrays including duplicates

Count how many car fleets arrive at the target

Implement bubble sort to sort an array in ascending order

Implement insertion sort — build sorted array one element at a time

Implement merge sort using divide-and-conquer

Implement quicksort with partition — the most important sort for interviews

Check if two strings are anagrams by sorting and comparing

Merge all overlapping intervals — classic FAANG sorting problem

Can a person attend all meetings? Check for overlapping intervals

Find minimum number of conference rooms needed

Arrange numbers to form the largest possible number

Sort characters by how often they appear, most frequent first

Sort array according to the order defined by another array

Move all even numbers before odd numbers

Find the kth largest element using QuickSelect (partition)

Insert a new interval and merge if necessary

Find minimum number of intervals to remove for no overlaps