Missing Problems Status

LeetCode Top 150 Problems - Coverage Status

Currently documenting 21 of 150 problems from the official LeetCode Top Interview 150 study plan.

Coverage: 14% — 129 problems remaining.

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Array / String 3 of 24

#	Problem	Status	Solution Languages
1	Two Sum	✅	6 languages
2	Remove Element	⬜	—
3	Remove Duplicates from Sorted Array	⬜	—
4	Remove Duplicates from Sorted Array II	⬜	—
5	Majority Element	✅	6 languages
6	Rotate Array	⬜	—
7	Best Time to Buy and Sell Stock	⬜	—
8	Best Time to Buy and Sell Stock II	⬜	—
9	Jump Game	⬜	—
10	Jump Game II	⬜	—
11	H-Index	⬜	—
12	Insert Delete GetRandom O(1)	⬜	—
13	Product of Array Except Self	✅	6 languages
14	Gas Station	⬜	—
15	Candy	⬜	—
16	Trapping Rain Water	✅	6 languages
17	Roman to Integer	⬜	—
18	Integer to Roman	⬜	—
19	Length of Last Word	⬜	—
20	Longest Common Prefix	⬜	—
21	Reverse Words in a String	⬜	—
22	Zigzag Conversion	⬜	—
23	Find the Index of the First Occurrence in a String	⬜	—
24	Text Justification	⬜	—

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Two Pointers 2 of 5

#	Problem	Status	Solution Languages
25	Valid Palindrome	✅	6 languages
26	Is Subsequence	⬜	—
27	Two Sum II - Input Array Is Sorted	✅	6 languages
28	Container With Most Water	✅	6 languages
29	3Sum	✅	6 languages

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Sliding Window 0 of 4

#	Problem	Status	Solution Languages
30	Minimum Size Subarray Sum	⬜	—
31	Longest Substring Without Repeating Characters	⬜	—
32	Substring with Concatenation of All Words	⬜	—
33	Minimum Window Substring	⬜	—

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Matrix 0 of 5

#	Problem	Status	Solution Languages
34	Valid Sudoku	✅	6 languages
35	Spiral Matrix	⬜	—
36	Rotate Image	⬜	—
37	Set Matrix Zeroes	⬜	—
38	Game of Life	⬜	—

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Hash Map 4 of 9

#	Problem	Status	Solution Languages
39	Ransom Note	⬜	—
40	Isomorphic Strings	⬜	—
41	Word Pattern	⬜	—
42	Valid Anagram	✅	6 languages
43	Group Anagrams	✅	6 languages
44	Two Sum	✅	6 languages
45	Happy Number	⬜	—
46	Contains Duplicate II	⬜	—
47	Longest Consecutive Sequence	✅	6 languages

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Intervals 0 of 4

#	Problem	Status	Solution Languages
48	Summary Ranges	⬜	—
49	Merge Intervals	⬜	—
50	Insert Interval	⬜	—
51	Minimum Number of Arrows to Burst Balloons	⬜	—

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Stack 0 of 5

#	Problem	Status	Solution Languages
52	Valid Parentheses	⬜	—
53	Simplify Path	⬜	—
54	Min Stack	⬜	—
55	Evaluate Reverse Polish Notation	⬜	—
56	Basic Calculator	⬜	—

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Linked List 0 of 11

#	Problem	Status	Solution Languages
57	Linked List Cycle	⬜	—
58	Add Two Numbers	⬜	—
59	Merge Two Sorted Lists	⬜	—
60	Copy List with Random Pointer	⬜	—
61	Reverse Linked List II	⬜	—
62	Reverse Nodes in k-Group	⬜	—
63	Remove Nth Node From End of List	⬜	—
64	Remove Duplicates from Sorted List II	⬜	—
65	Rotate List	⬜	—
66	Partition List	⬜	—
67	LRU Cache	⬜	—

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Binary Tree General 0 of 15

#	Problem	Status	Solution Languages
68	Maximum Depth of Binary Tree	⬜	—
69	Same Tree	⬜	—
70	Invert Binary Tree	⬜	—
71	Symmetric Tree	⬜	—
72	Construct Binary Tree from Preorder and Inorder Traversal	⬜	—
73	Construct Binary Tree from Inorder and Postorder Traversal	⬜	—
74	Populating Next Right Pointers in Each Node II	⬜	—
75	Flatten Binary Tree to Linked List	⬜	—
76	Path Sum	⬜	—
77	Sum Root to Leaf Numbers	⬜	—
78	Binary Tree Maximum Path Sum	⬜	—
79	Binary Search Tree Iterator	⬜	—
80	Count Complete Tree Nodes	⬜	—
81	Lowest Common Ancestor of a Binary Tree	⬜	—

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Binary Tree BFS 0 of 4

#	Problem	Status	Solution Languages
82	Binary Tree Right Side View	⬜	—
83	Average of Levels in Binary Tree	⬜	—
84	Binary Tree Level Order Traversal	⬜	—
85	Binary Tree Zigzag Level Order Traversal	⬜	—

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Binary Search Tree 0 of 3

#	Problem	Status	Solution Languages
86	Minimum Absolute Difference in BST	⬜	—
87	Kth Smallest Element in a BST	⬜	—
88	Validate Binary Search Tree	⬜	—

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Graph General 0 of 6

#	Problem	Status	Solution Languages
89	Number of Islands	⬜	—
90	Surrounded Regions	⬜	—
91	Clone Graph	⬜	—
92	Evaluate Division	⬜	—
93	Course Schedule	⬜	—
94	Course Schedule II	⬜	—

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Graph BFS 0 of 3

#	Problem	Status	Solution Languages
95	Snakes and Ladders	⬜	—
96	Minimum Genetic Mutation	⬜	—
97	Word Ladder	⬜	—

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Trie 0 of 3

#	Problem	Status	Solution Languages
98	Implement Trie (Prefix Tree)	⬜	—
99	Design Add and Search Words Data Structure	⬜	—
100	Word Search II	⬜	—

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Backtracking 0 of 7

#	Problem	Status	Solution Languages
101	Letter Combinations of a Phone Number	⬜	—
102	Combinations	⬜	—
103	Permutations	⬜	—
104	Combination Sum	⬜	—
105	N-Queens II	⬜	—
106	Generate Parentheses	⬜	—
107	Word Search	⬜	—

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Divide & Conquer 0 of 4

#	Problem	Status	Solution Languages
108	Convert Sorted Array to Binary Search Tree	⬜	—
109	Sort List	⬜	—
110	Construct Quad Tree	⬜	—
111	Merge k Sorted Lists	⬜	—

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Kadane’s Algorithm 0 of 2

#	Problem	Status	Solution Languages
112	Maximum Subarray	⬜	—
113	Maximum Sum Circular Subarray	⬜	—

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Binary Search 0 of 7

#	Problem	Status	Solution Languages
114	Search Insert Position	⬜	—
115	Search a 2D Matrix	⬜	—
116	Find Peak Element	⬜	—
117	Search in Rotated Sorted Array	⬜	—
118	Find First and Last Position of Element in Sorted Array	⬜	—
119	Find Minimum in Rotated Sorted Array	⬜	—
120	Median of Two Sorted Arrays	⬜	—

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Heap 0 of 4

#	Problem	Status	Solution Languages
121	Kth Largest Element in an Array	⬜	—
122	IPO	⬜	—
123	Find K Pairs with Smallest Sums	⬜	—
124	Find Median from Data Stream	⬜	—

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Bit Manipulation 1 of 6

#	Problem	Status	Solution Languages
125	Add Binary	⬜	—
126	Reverse Bits	⬜	—
127	Number of 1 Bits	⬜	—
128	Single Number	⬜	—
129	Single Number II	⬜	—
130	Bitwise AND of Numbers Range	⬜	—

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Math 1 of 6

#	Problem	Status	Solution Languages
131	Palindrome Number	✅	6 languages
132	Plus One	⬜	—
133	Factorial Trailing Zeroes	⬜	—
134	Sqrt(x)	⬜	—
135	Pow(x, n)	⬜	—
136	Max Points on a Line	⬜	—

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1D DP 0 of 5

#	Problem	Status	Solution Languages
137	Climbing Stairs	⬜	—
138	House Robber	⬜	—
139	Word Break	⬜	—
140	Coin Change	⬜	—
141	Longest Increasing Subsequence	⬜	—

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Multidimensional DP 0 of 9

#	Problem	Status	Solution Languages
142	Triangle	⬜	—
143	Minimum Path Sum	⬜	—
144	Unique Paths II	⬜	—
145	Longest Palindromic Substring	⬜	—
146	Interleaving String	⬜	—
147	Edit Distance	⬜	—
148	Best Time to Buy and Sell Stock III	⬜	—
149	Best Time to Buy and Sell Stock IV	⬜	—
150	Maximal Square	⬜	—

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Additional Problems (Not in Top 150)

These problems are documented but not part of the official Top 150:

#	Problem	Status
49	Group Anagrams	✅
50	Top K Frequent Elements	✅
238	Product of Array Except Self	✅
347	Top K Frequent Elements	✅
36	Valid Sudoku	✅
128	Longest Consecutive Sequence	✅
169	Majority Element	✅
268	Missing Number	✅
217	Contains Duplicate	✅
350	Intersection of Two Arrays II	✅
125	Valid Palindrome	✅
41	First Missing Positive	✅
42	Trapping Rain Water	✅
15	3Sum	✅
167	Two Sum II	✅
525	Contiguous Array	✅
560	Subarray Sum Equals K	✅

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Next Steps

High Priority (most commonly asked in interviews):

1. Sliding Window (0/4) — Start with #31 (Longest Substring Without Repeating Characters)
2. Linked List (0/11) — Start with #57 (Linked List Cycle)
3. Binary Tree (0/15) — Start with #68 (Maximum Depth)
4. Dynamic Programming (0/14) — Start with #137 (Climbing Stairs)

Medium Priority: 5. Stack operations (0/5) 6. Graph problems (0/9) 7. Binary Search (0/7)

Sources:

• LeetCode Top Interview 150
• NeetCode Top 150 Questions