In computer science, a trie, also called digital tree or prefix tree, is a kind of search tree—an ordered tree data structure used to store a dynamic set or associative array where the keys are usually strings.

Leetcode Data Structure Design Problem Set (1)

• 146.LRU Cache
• 284.Peeking Iterator
• 341.Flatten Nested List Iterator
• 295.Find Median from Data Stream

[Best Time to Buy and Sell Stock] Problem Set

Leetcode Dynamic Programming Problem Set (3)

• 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

Leetcode Dynamic Programming Problem Collection (2)

• 322.Coin Change
• 55.Jump Game
• 62.Unique Paths
• 300.Longest Increasing Subsequence
• 91.Decode Way

Two pointers problem set (2)

• 11.Container With Most Water
• 532.K-diff Pairs in an Array

N Sum problem set:

• 1.Two Sum
• 167.Two Sum II - Input array is sorted
• 15.3Sum
• 16.3Sum Closest
• 18.4Sum

Two pointers problem set (1) - Sliding Window

• 76.Minimum Window Substring
• 567.Permutation in String
• 438.Find All Anagrams in a String
• 3.Longest Substring Without Repeating Characters
• 239.Sliding Window Maximum

Leetcode Binary Search Problem Set (2) - Hard

• 410.Split Array Largest Sum

Classic binary search scenarios are find a number, and find boundaries.
Leetcode Binary Search Problem Set (1) - Medium

• 278.First Bad Version
• 33.Search in Rotated Sorted Array
• 1283.Find the Smallest Divisor Given a Threshold
• 875.Koko Eating Bananas
• 1011.Capacity To Ship Packages Within D Days
• 981.Time Based Key-Value Store

Leetcode backtracking problem collection (2) - Hard

• 51.N-Queens
• 37.Sudoku Solver

Backtracking is a general algorithm for finding all (or some) solutions to some computational problems.

Leetcode backtracking problem collection (1)

• 46.Permutations
• 78.Subsets
• 77.Combinations
• 39.Combination Sum
• 22.Generate Parentheses