Notes

Leetcode Problems by Category

Recursion and Backtracking

Two pointers

• 042. Trapping Rain Water
• 075. Sort Colors
• 1423. Maximum Points You Can Obtain from Cards
• 1695. Maximum Erasure Value
• 1793. Maximum Score of a Good Subarray

Binary Search (template)

• 0004. Median of Two Sorted Arrays
• 0033. Search in Rotated Sorted Array
• 0081. Search in Rotated Sorted Array II
• 153. Find Minimum in Rotated Sorted Array
• 0215. Kth Largest Element in an Array (QuickSelection)
• 0410. Split Array Largest Sum
• 774. Minimize Max Distance to Gas Station (H)
• 0875. Koko Eating Bananas
• 1011. Capacity To Ship Packages Within D Days
• 1283. Find the Smallest Divisor Given a Threshold
• 1482. Minimum Number of Days to Make m Bouquets

Hash Table

Heap

Tree

• 437. Path Sum III

Binary Tree / Binary Search Tree

• 0235. Lowest Common Ancestor of a Binary Search Tree
• 0236. Lowest Common Ancestor of a Binary Tree

Binary Index Tree / Fenwick Tree

• 307. Range Sum Query - Mutable
• 308. Range Sum Query 2D - Mutable
• 315. Count of Smaller Numbers After Self
• 327. Count of Range Sum
• 493. Reverse Pairs
• 1649. Create Sorted Array through Instructions

Segement Tree (template)

• 0307. Range Sum Query - Mutable

Design

Stack

• 1776. Car Fleet ii

Monotonic Stack/Queue

• 031. Next Permutation
• 042. Trapping Rain Water
• 084. Largest Rectangle in Histogram
• 239. Sliding Window Maximum
• 402. Remove K Digits (M)
• 456. 132 Pattern
• 496. Next Greater Element I
• 503. Next Greater Element II
• 739. Daily Temperatures
• 901. Online Stock Span
• 1130. Minimum Cost Tree From Leaf Values
• 1856. Maximum Subarray Min-Product

Deque

Monotonic Queue

• 239. Sliding Window Maximum ( )
• 862. Shortest Subarray with Sum at Least K

Monotonic Deque

• 975. Odd Even Jump (DP+Monotonic Deque)
• 1696. Jump-Game-VI (DP+Monotonic Deque)

DFS

• 200. Number of Islands
• 419. Battleships in a Board

BFS

Topological Sort

Dijkstra (BFS+PQ)

1631. Path With Minimum Effort

Trie (template)

• 0425. Word Squares
• 0336. Palindrome Pairs
• 0642. Design Search Autocomplete System

Greedy

LIS (Longest Increasing Subsequence)

Sort

• 164. Maxmum Gap
• 347. Top K Frequent Elements

Interval / Line Sweep (Sort+Heap) template

• 218. The Skyline Problem
• 621. Task Scheduler
• 630. Course Schedule III
• 646. Maximum Length of Pair Chain
• 759. Employee Free Time
• 1094. Car Pooling
• 1851. Minimum Interval to Include Each Query

Linked List

• 019. Remove Nth Node From End of List
• 024. Swap Nodes in Pairs
• 1721. Swapping Nodes in a Linked List

Dynamic Programming

• 121. Best Time to Buy and Sell Stock
• 122. Best Time to Buy and Sell Stock II
• 123. Best Time to Buy and Sell Stock III
• 188. Best Time to Buy and Sell Stock IV
• 309. Best Time to Buy and Sell Stock with Cooldown
• 714. Best Time to Buy and Sell Stock with Transaction Fee
• 823. Binary Trees With Factors
• 1000. Minimum Cost to Merge Stones

坐标型 Grid

序列 Sequence

• 300. Longest Increasing Subsequence

双序列 Two Sequence

• 044. Wildcard Matching
• 115. Distinct Subsequences

区间型 Interval

• 132. Palindrome Partitioning II

Bit Manipulation

• 698. Partition to K Equal Sum Subsets

Others

Line Sweep

• 0253. Meeting Rooms ii
• 0759. Employee Free Time

TBD

• 0912. Sort an Array
• 0451. Sort Characters by Frequency