Data Structures
Squares of a Sorted Array
Return the squares of a sorted array in sorted order using two pointers from both ends, in O(n) time.
Data Structures
Arrays, Strings, Sliding Window, Two Pointers, Searching & Binary Search, Sorting, Linked List, Stack & Queue, Recursion & Backtracking, Trees, Heap / Priority Queue, Graphs, Dynamic Programming, Greedy, Bit Manipulation, Trie, Math & Number Theory, Design (LLD / OOP), SQL, System Design (HLD)
180 notes in 20 topics
Topics in Data Structures
Arrays 30
Strings 35
Sliding Window 35
Two Pointers 30
Searching & Binary Search 30
Sorting 25
Linked List 0
Stack & Queue 0
Recursion & Backtracking 0
Trees 0
Heap / Priority Queue 0
Graphs 0
Dynamic Programming 0
Greedy 0
Bit Manipulation 0
Trie 0
Math & Number Theory 0
Design (LLD / OOP) 0
SQL 0
System Design (HLD) 0
Notes
Data Structures
Merge Two Sorted Arrays (Two Pointer)
Merge two sorted arrays in place using two pointers from the back, in O(m+n) time and O(1) space.
Data Structures
Intersection of Two Arrays II
Find the intersection of two arrays including duplicates using sorting and two pointers, in O(n log n) time.
Data Structures
Backspace String Compare
Compare two strings containing backspace characters using two pointers scanning from the end, in O(n) time and O(1) space.
Data Structures
Trapping Rain Water (Two Pointer Approach)
Compute how much rain water is trapped between bars using the two pointer technique with running max heights, in O(n) time and O(1) space.
Data Structures
Container With Most Water (Two Pointer Approach)
Find two lines that hold the most water using two pointers from both ends, moving the shorter line inward, in O(n) time.
Data Structures
Partition Labels
Partition a string into as many parts as possible so each letter appears in one part, using last-occurrence indices and an expanding window, in O(n) t...
Data Structures
Sort Colors (Dutch National Flag Two Pointer)
Sort an array of 0s, 1s, and 2s in a single pass using the Dutch National Flag three pointer technique, in O(n) time and O(1) space.
Data Structures
Remove Duplicates from Sorted Array II
Remove duplicates from a sorted array so each value appears at most twice, in place using the slow/fast two pointer pattern, in O(n) time.
Data Structures
Linked List Cycle Detection (Fast and Slow Pointers)
Detect a cycle in a linked list using Floyd’s fast and slow pointer algorithm, in O(n) time and O(1) space.
Data Structures
Middle of the Linked List
Find the middle node of a linked list in one pass using fast and slow pointers, in O(n) time and O(1) space.
Data Structures
Palindrome Linked List Check
Check if a linked list is a palindrome by finding the middle with fast/slow pointers, reversing the second half, and comparing, in O(n) time and O(1)...