AlgoMonster Coding Interivew problem frequency analysis

	A	B	C	D	E	F
1	Problem	Topic	One-off patterns		Topic	Number of problems
2	Two Sum			done	Two Pointers (inc. Sliding window and Prefix sum)	14
3	Number of Islands				BFS	6
4	Add Two Numbers	Math			DFS	18
5	Trapping Rain Water	Two Pointers			Heap	5
6	LRU Cache	Hash			Basic Programming	14
7	Longest Palindromic Substring	Two Pointers			Binary Search	5
8	Median of Two Sorted Arrays	Binary Search			Linked list classic	4
9	Valid Parentheses	Stack			Matrix
10	Merge Two Sorted Lists	Basic Programming			Tree classic
11	Longest Substring Without Repeating Characters	Two Pointers			Stack
12	Merge k Sorted Lists	Heap				66
13	3Sum	Two Pointers
14	Product of Array Except Self	Prefix Sum
15	Copy List with Random Pointer	Linked List	Classic
16	Merge Intervals	Interval/Sweep line
17	Best Time to Buy and Sell Stock	Sweep line	Classic
18	Maximum Subarray	Dynamic programming	Classic
19	Generate Parentheses	DFS
20	Reverse Linked List	Linked List	Classic
21	Search in Rotated Sorted Array	Binary Search	Classic
22	Alien Dictionary	BFS
23	Game of Life	Simulation
24	Meeting Rooms II	Sweep line	Classic
25	Coin Change	Dynamic programming
26	Serialize and Deserialize Binary Tree	DFS	Classic
27	Minimum Window Substring	Two Pointer	Classic
28	Spiral Matrix	Matrix	Classic
29	Word Break	DFS
30	Letter Combinations of a Phone Number	DFS
31	Container With Most Water	Two Pointers
32	First Missing Positive	Bucket Sort
33	Reverse Integer	Math
34	Search a 2D Matrix II	Binary Search
35	Regular Expression Matching	DFS
36	Binary Tree Maximum Path Sum	DFS
37	Word Search	DFS
38	Word Ladder	BFS
39	Permutations	DFS
40	Basic Calculator II	Stack
41	Find Median from Data Stream	Heap
42	Merge Sorted Array	Basic Programming	Classic
43	Kth Largest Element in an Array	Heap	Classic
44	Longest Consecutive Sequence	Sweep line
45	Fizz Buzz	Basic Programming
46	Decode Ways	DFS
47	Insert Delete GetRandom O(1)	Hash
48	Word Search II	DFS and BFS
49	Word Break II	DFS
50	Fraction to Recurring Decimal	Math
51	Happy Number	Basic Programming
52	Find First and Last Position of Element in Sorted Array	Binary Search
53	Flatten Nested List Iterator	Stack
54	Sliding Window Maximum	Monotonic stack
55	Validate Binary Search Tree	DFS
56	The Skyline Problem	Monotonic stack
57	Valid Palindrome	Two Pointers
58	Top K Frequent Elements	Heap
59	Lowest Common Ancestor of a Binary Tree	DFS
60	Roman to Integer	Basic Programming
61	Rotate Image	Matrix
62	Course Schedule II	DFS
63	Design Tic-Tac-Toe	Design
64	String to Integer (atoi)	Basic Programming
65	Construct Binary Tree from Preorder and Inorder Traversal	Divide and Conquer	Classic
66	First Unique Character in a String	Basic Programming
67	Group Anagrams	Basic Programming
68	Climbing Stairs	DFS
69	Longest Common Prefix	Basic Programming
70	Count of Smaller Numbers After Self	Divide and Conquer
71	Subsets	DFS
72	Count Primes	Math
73	Longest Substring with At Most K Distinct Characters	Two Pointers
74	Sort Colors	Two Pointers
75	Binary Tree Zigzag Level Order Traversal	BFS
76	Count and Say	Basic Programming
77	Course Schedule	BFS/Topologocal sort
78	Binary Tree Level Order Traversal	BFS
79	Pow(x, n)	Binary Search
80	Reverse String	Two Pointers
81	Gas Station	Greedy
82	House Robber	Dynamic programming
83	Sort List	Divide & Conque/Merge Sort
84	Missing Number	Basic Programming
85	Palindrome Linked List	Linked List
86	Valid Sudoku	Basic Programming
87	Valid Anagram	Basic Programming
88	Maximum Product Subarray	Min Max	classic
89	Divide Two Integers	Math
90	Move Zeroes	Two Pointers
91	Wildcard Matching	DFS
92	Find the Celebrity	Two Pointers
93	Largest Rectangle in Histogram	Monotonic Stack
94	Symmetric Tree	DFS
95	Largest Number	Sorting
96	Jump Game	Greedy
97	Remove Nth Node From End of List	Linked List
98	Longest Increasing Subsequence	DFS		memoization
99	Populating Next Right Pointers in Each Node	BFS
100	Max Points on a Line	Math