tcs LeetCode Questions

228 questions all-time · 99 easy · 108 medium · 21 hard

#	Problem	Difficulty	Frequency	Acceptance
1	Friday Purchases I Database	Medium	100	0.8%
2	Two Sum Array, Hash Table	Easy	87	0.6%
3	Longest Palindromic Substring Two Pointers, String, Dynamic Programming	Medium	77	0.4%
4	Palindrome Number Math	Easy	77	0.6%
5	Maximum Subarray Array, Divide and Conquer, Dynamic Programming	Medium	73	0.5%
6	Move Zeroes Array, Two Pointers	Easy	72	0.6%
7	Majority Element Array, Hash Table, Divide and Conquer, Sorting, Counting	Easy	67	0.7%
8	Longest Common Prefix Array, String, Trie	Easy	66	0.5%
9	Best Time to Buy and Sell Stock Array, Dynamic Programming	Easy	65	0.6%
10	Sort Colors Array, Two Pointers, Sorting	Medium	63	0.7%
11	Find the Index of the First Occurrence in a String Two Pointers, String, String Matching	Easy	62	0.5%
12	Valid Parentheses String, Stack	Easy	62	0.4%
13	Single Number Array, Bit Manipulation	Easy	62	0.8%
14	Second Highest Salary Database	Medium	62	0.5%
15	Valid Anagram Hash Table, String, Sorting	Easy	62	0.7%
16	Longest Substring Without Repeating Characters Hash Table, String, Sliding Window	Medium	61	0.4%
17	Subarray Sum Equals K Array, Hash Table, Prefix Sum	Medium	61	0.5%
18	Rotate Array Array, Math, Two Pointers	Medium	59	0.5%
19	Median of Two Sorted Arrays Array, Binary Search, Divide and Conquer	Hard	59	0.5%
20	Reverse Integer Math	Medium	57	0.3%
21	Container With Most Water Array, Two Pointers, Greedy	Medium	57	0.6%
22	3Sum Array, Two Pointers, Sorting	Medium	57	0.4%
23	Remove Duplicates from Sorted Array Array, Two Pointers	Easy	57	0.6%
24	Jump Game Array, Dynamic Programming, Greedy	Medium	57	0.4%
25	Contains Duplicate Array, Hash Table, Sorting	Easy	57	0.6%
26	Remove Letter To Equalize Frequency Hash Table, String, Counting	Easy	57	0.2%
27	Count the Digits That Divide a Number Math	Easy	57	0.9%
28	Maximum Ascending Subarray Sum Array	Easy	57	0.7%
29	Maximum Product Subarray Array, Dynamic Programming	Medium	56	0.4%
30	Reverse String Two Pointers, String	Easy	56	0.8%
31	Minimum Cuts to Divide a Circle Math, Geometry	Easy	56	0.6%
32	Minimum Operations to Exceed Threshold Value I Array	Easy	56	0.9%
33	Minimum Operations to Exceed Threshold Value II Array, Heap (Priority Queue), Simulation	Medium	56	0.5%
34	Palindrome Partitioning IV String, Dynamic Programming	Hard	56	0.5%
35	Check if Array Is Sorted and Rotated Array	Easy	56	0.6%
36	Valid Palindrome Two Pointers, String	Easy	56	0.5%
37	Zigzag Grid Traversal With Skip Array, Matrix, Simulation	Easy	56	0.7%
38	Task Scheduler Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting	Medium	56	0.6%
39	Spiral Matrix Array, Matrix, Simulation	Medium	54	0.6%
40	Find First and Last Position of Element in Sorted Array Array, Binary Search	Medium	51	0.5%
41	Trapping Rain Water Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack	Hard	51	0.7%
42	Pow(x, n) Math, Recursion	Medium	51	0.4%
43	First Unique Character in a String Hash Table, String, Queue, Counting	Easy	51	0.7%
44	Contains Duplicate II Array, Hash Table, Sliding Window	Easy	51	0.5%
45	Climbing Stairs Math, Dynamic Programming, Memoization	Easy	49	0.5%
46	Merge Sorted Array Array, Two Pointers, Sorting	Easy	49	0.6%
47	Toeplitz Matrix Array, Matrix	Easy	49	0.7%
48	Bitwise ORs of Subarrays Array, Dynamic Programming, Bit Manipulation	Medium	49	0.6%
49	Fibonacci Number Math, Dynamic Programming, Recursion, Memoization	Easy	49	0.7%
50	Merge Intervals Array, Sorting	Medium	49	0.5%
51	Burst Balloons Array, Dynamic Programming	Hard	49	0.6%
52	Search in Rotated Sorted Array Array, Binary Search	Medium	49	0.5%
53	Roman to Integer Hash Table, Math, String	Easy	46	0.7%
54	Unique Paths Math, Dynamic Programming, Combinatorics	Medium	46	0.7%
55	Plus One Array, Math	Easy	46	0.5%
56	Missing Number Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting	Easy	46	0.7%
57	Add Binary Math, String, Bit Manipulation, Simulation	Easy	46	0.6%
58	Single Element in a Sorted Array Array, Binary Search	Medium	46	0.6%
59	Sort an Array Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort	Medium	46	0.6%
60	Search Insert Position Array, Binary Search	Easy	46	0.5%
61	N-Queens Array, Backtracking	Hard	46	0.8%
62	Smallest Sufficient Team Array, Dynamic Programming, Bit Manipulation, Bitmask	Hard	46	0.6%
63	Employees Earning More Than Their Managers Database	Easy	46	0.7%
64	Add Two Numbers Linked List, Math, Recursion	Medium	42	0.5%
65	4Sum Array, Two Pointers, Sorting	Medium	42	0.4%
66	Generate Parentheses String, Dynamic Programming, Backtracking	Medium	42	0.8%
67	Length of Last Word String	Easy	42	0.6%
68	Set Matrix Zeroes Array, Hash Table, Matrix	Medium	42	0.6%
69	Sqrt(x) Math, Binary Search	Easy	42	0.4%
70	Pascal's Triangle Array, Dynamic Programming	Easy	42	0.8%
71	Happy Number Hash Table, Math, Two Pointers	Easy	42	0.6%
72	Find the Duplicate Number Array, Two Pointers, Binary Search, Bit Manipulation	Medium	42	0.6%
73	Split Array With Same Average Array, Hash Table, Math, Dynamic Programming, Bit Manipulation, Bitmask	Hard	42	0.3%
74	Count Number of Pairs With Absolute Difference K Array, Hash Table, Counting	Easy	42	0.9%
75	Group Anagrams Array, Hash Table, String, Sorting	Medium	42	0.7%
76	Remove Nth Node From End of List Linked List, Two Pointers	Medium	42	0.5%
77	House Robber Array, Dynamic Programming	Medium	42	0.5%
78	Min Stack Stack, Design	Medium	42	0.6%
79	Middle of the Linked List Linked List, Two Pointers	Easy	42	0.8%
80	Duplicate Emails Database	Easy	42	0.7%
81	Squares of a Sorted Array Array, Two Pointers, Sorting	Easy	42	0.7%
82	Next Permutation Array, Two Pointers	Medium	38	0.5%
83	Reverse Words in a String Two Pointers, String	Medium	38	0.6%
84	Sliding Window Maximum Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue	Hard	38	0.5%
85	Diameter of Binary Tree Tree, Depth-First Search, Binary Tree	Easy	38	0.7%
86	Partition Equal Subset Sum Array, Dynamic Programming	Medium	38	0.5%
87	Tallest Billboard Array, Dynamic Programming	Hard	38	0.5%
88	Maximum Product of Three Numbers Array, Math, Sorting	Easy	38	0.5%
89	Serialize and Deserialize Binary Tree String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree	Hard	38	0.6%
90	Maximum Average Subarray I Array, Sliding Window	Easy	38	0.5%
91	Search in Rotated Sorted Array II Array, Binary Search	Medium	38	0.4%
92	Product Sales Analysis I Database	Easy	38	0.9%
93	Subsets II Array, Backtracking, Bit Manipulation	Medium	38	0.6%
94	Letter Combinations of a Phone Number Hash Table, String, Backtracking	Medium	38	0.7%
95	Find Minimum in Rotated Sorted Array Array, Binary Search	Medium	38	0.5%
96	String to Integer (atoi) String	Medium	38	0.2%
97	Longest Palindromic Subsequence String, Dynamic Programming	Medium	38	0.7%
98	Two Sum II - Input Array Is Sorted Array, Two Pointers, Binary Search	Medium	38	0.7%
99	Product of Array Except Self Array, Prefix Sum	Medium	38	0.7%
100	Merge Two Sorted Lists Linked List, Recursion	Easy	33	0.7%
101	Subsets Array, Backtracking, Bit Manipulation	Medium	33	0.8%
102	Best Time to Buy and Sell Stock II Array, Dynamic Programming, Greedy	Medium	33	0.7%
103	Largest Number Array, String, Greedy, Sorting	Medium	33	0.4%
104	Department Top Three Salaries Database	Hard	33	0.6%
105	Count Primes Array, Math, Enumeration, Number Theory	Medium	33	0.4%
106	Fizz Buzz Math, String, Simulation	Easy	33	0.8%
107	K-diff Pairs in an Array Array, Hash Table, Two Pointers, Binary Search, Sorting	Medium	33	0.5%
108	Find Customer Referee Database	Easy	33	0.7%
109	Peak Index in a Mountain Array Array, Binary Search	Medium	33	0.7%
110	Article Views I Database	Easy	33	0.8%
111	Recyclable and Low Fat Products Database	Easy	33	0.9%
112	Maximal Rectangle Array, Dynamic Programming, Stack, Matrix, Monotonic Stack	Hard	33	0.6%
113	Max Consecutive Ones Array	Easy	33	0.7%
114	Project Employees I Database	Easy	33	0.7%
115	Number of Good Pairs Array, Hash Table, Math, Counting	Easy	33	0.9%
116	Jump Game II Array, Dynamic Programming, Greedy	Medium	33	0.4%
117	Binary Tree Maximum Path Sum Dynamic Programming, Tree, Depth-First Search, Binary Tree	Hard	33	0.4%
118	Merge k Sorted Lists Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort	Hard	33	0.6%
119	Ugly Number Math	Easy	33	0.4%
120	Koko Eating Bananas Array, Binary Search	Medium	33	0.5%
121	Minimum Moves to Equal Array Elements II Array, Math, Sorting	Medium	33	0.6%
122	LRU Cache Hash Table, Linked List, Design, Doubly-Linked List	Medium	33	0.5%
123	Delete the Middle Node of a Linked List Linked List, Two Pointers	Medium	33	0.6%
124	Third Maximum Number Array, Sorting	Easy	33	0.4%
125	First Missing Positive Array, Hash Table	Hard	33	0.4%
126	Find Subsequence of Length K With the Largest Sum Array, Hash Table, Sorting, Heap (Priority Queue)	Easy	33	0.6%
127	Longest Subarray of 1's After Deleting One Element Array, Dynamic Programming, Sliding Window	Medium	33	0.7%
128	Water Bottles Math, Simulation	Easy	33	0.7%
129	Next Greater Element I Array, Hash Table, Stack, Monotonic Stack	Easy	33	0.8%
130	Assign Cookies Array, Two Pointers, Greedy, Sorting	Easy	33	0.6%
131	Remove Element Array, Two Pointers	Easy	33	0.6%
132	Non-overlapping Intervals Array, Dynamic Programming, Greedy, Sorting	Medium	33	0.6%
133	Range Sum Query - Immutable Array, Design, Prefix Sum	Easy	33	0.7%
134	Remove Duplicates from Sorted List Linked List	Easy	33	0.6%
135	Customer Who Visited but Did Not Make Any Transactions Database	Easy	33	0.7%
136	Longest Increasing Subsequence Array, Binary Search, Dynamic Programming	Medium	33	0.6%
137	String Compression Two Pointers, String	Medium	33	0.6%
138	Maximum Total Subarray Value I Array, Greedy	Medium	33	0.7%
139	Palindrome Linked List Linked List, Two Pointers, Stack, Recursion	Easy	33	0.6%
140	Remove Duplicates from Sorted Array II Array, Two Pointers	Medium	25	0.6%
141	Longest Consecutive Sequence Array, Hash Table, Union-Find	Medium	25	0.5%
142	Reverse Linked List Linked List, Recursion	Easy	25	0.8%
143	Power of Two Math, Bit Manipulation, Recursion	Easy	25	0.5%
144	Employee Bonus Database	Easy	25	0.8%
145	Binary Search Array, Binary Search	Easy	25	0.6%
146	Unique Paths II Array, Dynamic Programming, Matrix	Medium	25	0.4%
147	The kth Factor of n Math, Number Theory	Medium	25	0.7%
148	Integer to English Words Math, String, Recursion	Hard	25	0.4%
149	Divisor Game Math, Dynamic Programming, Brainteaser, Game Theory	Easy	25	0.7%
150	Maximum Swap Math, Greedy	Medium	25	0.5%
151	Majority Element II Array, Hash Table, Sorting, Counting	Medium	25	0.6%
152	String Compression III String	Medium	25	0.7%
153	Maximum Sum of Distinct Subarrays With Length K Array, Hash Table, Sliding Window	Medium	25	0.4%
154	Linked List Cycle Hash Table, Linked List, Two Pointers	Easy	25	0.5%
155	Running Sum of 1d Array Array, Prefix Sum	Easy	25	0.9%
156	Minimum Cost to Make at Least One Valid Path in a Grid Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path	Hard	25	0.7%
157	Replace Employee ID With The Unique Identifier Database	Easy	25	0.8%
158	Permutation in String Hash Table, Two Pointers, String, Sliding Window	Medium	25	0.5%
159	Check If Array Pairs Are Divisible by k Array, Hash Table, Counting	Medium	25	0.5%
160	Rotate Image Array, Math, Matrix	Medium	25	0.8%
161	Find K Closest Elements Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)	Medium	25	0.5%
162	Count the Number of Fair Pairs Array, Two Pointers, Binary Search, Sorting	Medium	25	0.5%
163	Return Length of Arguments Passed	Easy	25	0.9%
164	Remove All Occurrences of a Substring String, Stack, Simulation	Medium	25	0.8%
165	Repeated Substring Pattern String, String Matching	Easy	25	0.5%
166	Find the Original Typed String I String	Easy	25	0.7%
167	Maximum Gap Array, Sorting, Bucket Sort, Radix Sort	Medium	25	0.5%
168	Maximum Number of Events That Can Be Attended II Array, Binary Search, Dynamic Programming, Sorting	Hard	25	0.6%
169	Odd Even Linked List Linked List	Medium	25	0.6%
170	Convert Sorted List to Binary Search Tree Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree	Medium	25	0.7%
171	Subarray Product Less Than K Array, Binary Search, Sliding Window, Prefix Sum	Medium	25	0.5%
172	Valid Word String	Easy	25	0.5%
173	Maximum Nesting Depth of the Parentheses String, Stack	Easy	25	0.8%
174	Linked List Cycle II Hash Table, Linked List, Two Pointers	Medium	25	0.6%
175	Teemo Attacking Array, Simulation	Easy	25	0.6%
176	Distribute Coins in Binary Tree Tree, Depth-First Search, Binary Tree	Medium	25	0.8%
177	Minimum Size Subarray Sum Array, Binary Search, Sliding Window, Prefix Sum	Medium	25	0.5%
178	Binary Tree Inorder Traversal Stack, Tree, Depth-First Search, Binary Tree	Easy	25	0.8%
179	Smallest Integer Divisible by K Hash Table, Math	Medium	25	0.5%
180	Department Highest Salary Database	Medium	25	0.6%
181	How Many Numbers Are Smaller Than the Current Number Array, Hash Table, Sorting, Counting Sort	Easy	25	0.9%
182	Reorder List Linked List, Two Pointers, Stack, Recursion	Medium	25	0.7%
183	Bulb Switcher Math, Brainteaser	Medium	25	0.6%
184	Regular Expression Matching String, Dynamic Programming, Recursion	Hard	25	0.3%
185	Managers with at Least 5 Direct Reports Database	Medium	25	0.5%
186	Intersection of Two Arrays II Array, Hash Table, Two Pointers, Binary Search, Sorting	Easy	25	0.6%
187	Rotting Oranges Array, Breadth-First Search, Matrix	Medium	25	0.6%
188	Longest Balanced Substring II Hash Table, String, Prefix Sum	Medium	25	0.4%
189	Count and Say String	Medium	25	0.6%
190	Integer to Roman Hash Table, Math, String	Medium	25	0.7%
191	Number of Islands Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix	Medium	25	0.6%
192	Daily Temperatures Array, Stack, Monotonic Stack	Medium	25	0.7%
193	Convert a Number to Hexadecimal Math, String, Bit Manipulation	Easy	25	0.5%
194	Continuous Subarray Sum Array, Hash Table, Math, Prefix Sum	Medium	25	0.3%
195	Longest Common Subsequence String, Dynamic Programming	Medium	25	0.6%
196	Reshape the Matrix Array, Matrix, Simulation	Easy	25	0.7%
197	Permutations Array, Backtracking	Medium	25	0.8%
198	Zigzag Conversion String	Medium	25	0.5%
199	Longest Palindrome Hash Table, String, Greedy	Easy	25	0.6%
200	Search a 2D Matrix Array, Binary Search, Matrix	Medium	25	0.5%
201	Find the Winner of the Circular Game Array, Math, Recursion, Queue, Simulation	Medium	25	0.8%
202	Intersection of Two Linked Lists Hash Table, Linked List, Two Pointers	Easy	25	0.6%
203	Word Ladder Hash Table, String, Breadth-First Search	Hard	25	0.5%
204	Remove Outermost Parentheses String, Stack	Easy	25	0.9%
205	Min Cost Climbing Stairs Array, Dynamic Programming	Easy	25	0.7%
206	Create Hello World Function	Easy	25	0.8%
207	Rotate String String, String Matching	Easy	25	0.7%
208	Swap Nodes in Pairs Linked List, Recursion	Medium	25	0.7%
209	Find Smallest Letter Greater Than Target Array, Binary Search	Easy	25	0.6%
210	Find Numbers with Even Number of Digits Array, Math	Easy	25	0.8%
211	3Sum Closest Array, Two Pointers, Sorting	Medium	25	0.5%
212	Find Pivot Index Array, Prefix Sum	Easy	25	0.6%
213	Top K Frequent Elements Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect	Medium	25	0.7%
214	Minimum Depth of Binary Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree	Easy	25	0.5%
215	Insert Interval Array	Medium	25	0.5%
216	Sort Array By Parity Array, Two Pointers, Sorting	Easy	25	0.8%
217	Subtract the Product and Sum of Digits of an Integer Math	Easy	25	0.9%
218	Delete Duplicate Emails Database	Easy	25	0.7%
219	Spiral Matrix II Array, Matrix, Simulation	Medium	25	0.8%
220	Multiply Strings Math, String, Simulation	Medium	25	0.4%
221	Same Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree	Easy	25	0.7%
222	Find All Numbers Disappeared in an Array Array, Hash Table	Easy	25	0.6%
223	Contiguous Array Array, Hash Table, Prefix Sum	Medium	25	0.5%
224	Maximum Depth of Binary Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree	Easy	25	0.8%
225	Maximum Ice Cream Bars Array, Greedy, Sorting, Counting Sort	Medium	25	0.8%
226	Binary Subarrays With Sum Array, Hash Table, Sliding Window, Prefix Sum	Medium	25	0.7%
227	Consecutive Numbers Database	Medium	25	0.5%
228	Largest Rectangle in Histogram Array, Stack, Monotonic Stack	Hard	25	0.5%

How to read this list

The tabs at the top split the questions by how recently people said they were asked in interviews. "Last 30 Days" is the past month, "Last 3 Months" is the past quarter, and so on. "All Time" is every question on record for this company.

Frequency is a score from 0 to 100 for how often a question showed up in that time window. A higher number means it came up more often, so the list starts with the most common questions first. Acceptance is the share of submissions that pass on LeetCode. Click any question to open it on LeetCode.