1 |
2-Sum problem |
Google |
Solved |
Python, C++, Java |
2 |
Product except self |
Uber |
Solved |
Python, C++ |
3 |
Serialize and Deserialize Binary Trees |
Google |
Solved |
Python, C++ |
4 |
First missing positive |
Stripe |
Solved |
Python, C++ |
5 |
car, cdr, cons |
Jane Street |
Solved |
Python, C++ |
6 |
XOR Linked list |
Google |
Solved |
C++ |
7 |
Number of ways to decode a message |
Facebook |
Solved |
Python, C++ |
8 |
Universal Value Tree Count |
Google |
Solved |
Python, C++ |
9 |
Largest sum of non-adjacent numbers in array |
Airbnb |
Solved |
Python, C++ |
10 |
Job Scheduler |
Apple |
Solved |
Python, C++ |
11 |
Autocomplete system |
Twitter |
Solved |
Python, C++ |
12 |
Number of ways to climb a staircase |
Amazon |
Solved |
Python |
13 |
Longest substring with at most K distinct characters |
Amazon |
Solved |
Python |
14 |
Pi estimation using Monte Carlo method |
Google |
Solved |
Python |
15 |
Random element from large input stream |
Facebook |
Solved |
Python |
16 |
Order Log |
Twitter |
Solved |
Python |
17 |
Longest absolute path in file structure |
Google |
Solved |
Python |
18 |
Max of each Subarray |
Google |
Solved |
Python |
19 |
House paint problem |
Facebook |
Solved |
Java |
20 |
Intersecting Linked Lists |
Google |
Solved |
Python |
21 |
Classroom Scheduling problem |
Snapchat |
Solved |
Python |
22 |
Word Break |
Microsoft |
Solved |
Python |
23 |
Number of ways to go from A to B |
Google |
Unsolved |
|
24 |
Binary Tree Locking |
Google |
Solved |
Python |
25 |
Regular Expression Implementation |
Facebook |
Unsolved |
|
26 |
Remove kth last element in linked list |
Google |
Solved |
Python |
27 |
Balanced parantheses |
Facebook |
Unsolved |
|
28 |
Justify text |
Palantir |
Solved |
Python |
29 |
Run length encoding |
Amazon |
Solved |
Python |
30 |
Elevation map |
Facebook |
Solved |
Python, C++ |
31 |
Minimum edit distance between two strings |
Google |
Unsolved |
|
32 |
Currency Exchange |
Jane Street |
Unsolved |
|
33 |
Running Median |
Microsoft |
Solved |
Python |
34 |
Minimum insertion palindrome |
Quora |
Unsolved |
|
35 |
Swap RGB array in-place |
Google |
Solved |
Python |
36 |
Second largest node in binary tree |
Dropbox |
Solved |
Python |
37 |
Power Set |
Google |
Solved |
Python |
38 |
Non-threatening Queens |
Microsoft |
Solved |
Python |
39 |
Conway's Game of Life |
Dropbox |
Unsolved |
|
40 |
Non-duplicated item in array |
Google |
Solved |
Python |
41 |
Flight itinerary |
Facebook |
Solved |
Python |
42 |
K sum subset |
Google |
Solved |
Python |
43 |
Stack Implementation |
Amazon |
Solved |
Python |
44 |
Count inversions |
Google |
Solved |
Python |
45 |
Random number generator |
Two Sigma |
Solved |
Python |
46 |
Longest palindromic substring |
Amazon |
Solved |
Python |
47 |
Maximum stock profit |
Facebook |
Solved |
Python |
48 |
Reconstruct binary tree given preorder and postorder traversals |
Google |
Solved |
Python |
49 |
Max Sum Subarray or Kadane's algorithm |
Amazon |
Solved |
Python |
50 |
Binary Tree Arithmetic |
Microsoft |
Solved |
Python, C++ |
51 |
Deck shuffling with swaps only |
Facebook |
Solved |
Python |
52 |
LRU Cache Implementation |
Google |
Solved |
Python |
53 |
Queue Implementation |
Apple |
Solved |
Python |
54 |
Sudoku solver |
Dropbox |
Solved |
Python |
55 |
URL shortener |
Microsoft |
Solved |
Python |
56 |
Graph Coloring |
Google |
Solved |
Python |
57 |
String Break |
Amazon |
Solved |
Python |
58 |
Rotated sorted array search |
Amazon |
Solved |
Python |
59 |
File Syncing between two computers |
Google |
Unsolved |
|
60 |
Equal Sum Partition |
Facebook |
Solved |
Python |
61 |
Integer exponentiation |
Google |
Solved |
Python |
62 |
Top-Left to Bottom-Right |
Facebook |
Solved |
Python |
63 |
Word Matrix |
Microsoft |
Solved |
Python |
64 |
Knight's Tour |
Google |
Solved |
Python |
65 |
Spiral Matrix |
Amazon |
Solved |
Python |
66 |
Unbiased Toss |
Square |
Solved |
Python |
67 |
LFU Cache Implementation |
Google |
Solved |
Python |
68 |
Attacking Bishops |
Google |
Solved |
Python |
69 |
Max triplet product |
Facebook |
Solved |
Python |
70 |
Perfect Numbers |
Microsoft |
Solved |
Python |
71 |
Another Random Number Generator |
Microsoft |
Solved |
Python |
72 |
Largest Value Path in a Directed Graph |
Google |
Solved |
Python |
73 |
Reverse Linked List in-place |
Google |
Solved |
Python |
74 |
Count occurrences in multiplication table |
Apple |
Solved |
Python |
75 |
Largest increasing subsequence |
Microsoft |
Solved |
Python |
76 |
Lexicographic matrix sort |
Google |
Solved |
Python |
77 |
Merge overlapping intervals |
Snapchat |
Solved |
Python |
78 |
Mergesort linked lists |
Google |
Solved |
Python |
79 |
Modifiabale non-decreasing array |
Facebook |
Solved |
Python |
80 |
Deepest Node in Binary Tree |
Google |
Solved |
Python, C++ |
81 |
Letter Combinations from Dictionary |
Yelp |
Solved |
Python |
82 |
Implementation of readN(n) using read7 |
Microsoft |
Solved |
Python |
83 |
Reverse Binary Tree |
Google |
Solved |
Python |
84 |
Island Count |
Amazon |
Solved |
Python |
85 |
X or Y |
Facebook |
Solved |
Python |
86 |
Min parantheses removal |
Google |
Solved |
Python |
87 |
Validate Map |
Uber |
Solved |
Python |
88 |
Integer division |
ContextLogic |
Solved |
Python |
89 |
Valid BST |
LinkedIn |
Solved |
Python |
90 |
Random number generator with exception rule |
Google |
Solved |
Python |
91 |
Function correction |
Dropbox |
Solved |
Python |
92 |
Valid Course Ordering |
Airbnb |
Solved |
Python |
93 |
Largest BST Size |
Apple |
Solved |
Python |
94 |
Tree Maximum Path Sum between 2 Leaves |
Google |
Solved |
Python |
95 |
Next greater permutation |
Palantir |
Solved |
Python |
96 |
All permutations |
Microsoft |
Solved |
Python |
97 |
Time-based Map |
Stripe |
Solved |
Python |
98 |
Find Word in Grid |
Coursera |
Solved |
Python |
99 |
Longest Continuous Sequence |
Microsoft |
Solved |
Python |
100 |
Minimum Step Move |
Google |
Solved |
Python |
101 |
Goldbach conjecture |
Alibaba |
Solved |
Python, C++ |
102 |
Continuous subarray sum equals K |
Lyft |
Solved |
Python |
103 |
Shortest substring containing given characters |
Square |
Solved |
Python |
104 |
Palindrome Linked List |
Google |
Solved |
Python |
105 |
Function Debounce |
Facebook |
Solved |
Python |
106 |
Hop array to other end |
Pinterest |
Solved |
Python, C++ |
107 |
Print binary tree level-wise |
Microsoft |
Solved |
Python, C++ |
108 |
String shift and check equality |
Google |
Solved |
Python |
109 |
Swap even and odd bits |
Cisco |
Solved |
Python |
110 |
All paths in a binary tree |
Facebook |
Solved |
Python |
111 |
Anagram start-indices in a string |
Google |
Solved |
Python |
112 |
LCA of Binary Tree |
Twitter |
Solved |
Python, C++ |
113 |
Reverse words in a string |
Google |
Solved |
Python, C++ |
114 |
Reverse words in string with delimiters relative order |
Facebook |
Solved |
Python, C++ |
115 |
Check whether one binary tree is subtree of another |
Google |
Solved |
C++ |
116 |
Generate arbitrarily sized binary tree |
Jane Street |
Solved |
C++ |
117 |
Max Level sum in a binary tree |
Facebook |
Solved |
C++ |
118 |
Sort squares of elements in sorted array |
Google |
Solved |
C++ |
120 |
Singleton pattern with twist |
Microsoft |
Solved |
Python |
121 |
Make palindrome with minimum deletions |
Google |
Solved |
C++, Python |
122 |
Collect maximum coins in 2-D matrix |
Zillow |
Solved |
C++, Python |
123 |
Does string represent a number |
LinkedIn |
Solved |
C++ |
124 |
Flip coins till only one remains |
Microsoft |
Solved |
C++ |
125 |
2-Sum problem in binary tree |
Google |
Solved |
C++ |
126 |
Rotate array in-place |
Facebook |
Solved |
C++ |
127 |
Add numbers represented as linked list |
Microsoft |
Solved |
C++ |
128 |
Tower of Hanoi |
|
Solved |
C++ |
129 |
Square root of a real number |
|
Solved |
C++ |
130 |
Maximum profit from k buy-sells |
Facebook |
Solved |
C++ |
131 |
Deep clone linked list having a random pointer at each node |
Snapchat |
Solved |
C++ |
132 |
Hit Counter class implementation |
Riot Games |
Solved |
C++ |
133 |
In-Order successor of a node in a binary tree |
Amazon |
Solved |
C++ |
134 |
Large sparse array data structure |
Facebook |
Solved |
C++ |
135 |
Min root to leaf sum path in binary tree |
Apple |
Solved |
C++ |
136 |
Largest rectangle in a matrix |
Google |
Solved |
C++ |
137 |
Bit array implementation |
Amazon |
Solved |
C++ |
138 |
Minimum coins for n cents |
Google |
Solved |
C++ |
139 |
Peekable iterator |
Google |
Solved |
Python |
140 |
Which two elements occur once in array |
Facebook |
Solved |
C++ |
141 |
3 stacks implementation |
Microsoft |
Solved |
C++ |
142 |
Balanced parantheses - II |
Google |
|
|
143 |
List partitioning |
Amazon |
Solved |
C++ |
144 |
Nearest larger number in an array |
Google |
Solved |
C++ |
145 |
Pairwise swap linked list nodes |
Google |
Solved |
C++ |
146 |
Binary tree pruning |
BufferBox |
Solved |
C++ |
147 |
Pancake Sort |
|
Solved |
C++ |
148 |
Subarray sum |
Goldman Sachs |
Solved |
C++ |
149 |
Gray code |
Apple |
Solved |
C++ |
150 |
K nearest neighbors |
LinkedIn |
Solved |
C++ |
151 |
Color image |
|
Solved |
C++ |
152 |
Random number generator |
Triplebyte |
Solved |
C++ |
153 |
Minimum word distance |
|
Solved |
C++ |
154 |
Stack implementation using heap API |
Amazon |
Solved |
C++ |
155 |
Majority Element |
MongoDB |
Solved |
C++ |
156 |
smallest number of squared integers which sum to n |
Facebook |
Solved |
C++ |
157 |
Palindrome string permutation possible |
Amazon |
Solved |
C++ |
158 |
Walled fort |
|
Solved |
C++ |
159 |
First recurring character in string |
Google |
Solved |
C++ |
160 |
Longest path in tree |
Uber |
|
|
161 |
Reverse bits |
Facebook |
Solved |
C++ |
162 |
Shortest unique prefix |
Square |
|
|
163 |
Reverse Polish notation |
Jane Street |
Solved |
C++ |
164 |
Find the only duplicate in array |
Google |
Solved |
C++ |
165 |
Number of smaller elements to the right in an array |
Google |
Solved |
C++ |
166 |
2-D iterator class |
Uber |
Solved |
C++ |
167 |
Palindrome concatenation pairs |
Airbnb |
Solved |
C++ |
168 |
Rotate 2-D array in-place |
Facebook |
Solved |
C++ |
169 |
Sort a linked list |
Google |
Solved |
C++ |
170 |
Shortest transformation from start word to end word |
Facebook |
|
|
171 |
Busiest time interval from a register |
Amazon |
Solved |
C++ |
172 |
Starting indices of word concatenations in a string |
Dropbox |
|
|
173 |
Flatten a nested dictionary |
Stripe |
Solved |
Python |
174 |
Polymorphism examples |
Microsoft |
Solved |
C++ |
175 |
Markov chain simulation |
Google |
Solved |
C++ |
176 |
One-to-one character mapping between two strings |
Bloomberg |
Solved |
C++ |
177 |
Rotate a linked list |
Airbnb |
Solved |
C++ |
178 |
Dice Simulation |
Two Sigma |
Solved |
C++ |
179 |
Recover BST from its postorder traversal |
Google |
Solved |
C++ |
180 |
Interleave two halves of a stack using a queue |
Google |
Solved |
C++ |
181 |
Minimum number of palindromes in a string |
Google |
|
|
182 |
Minimally connected graph |
Facebook |
Solved |
C++ |
183 |
What happens when you type a URL |
Twitch |
Solved |
NA |
184 |
Calculate GCD of numbers |
Amazon |
Solved |
C++ |
185 |
Calculate intersection area |
Google |
Solved |
C++ |
186 |
Divide array into 2 subsets with min difference of subset sums |
Microsoft |
|
|
187 |
Overlapping rectangles |
Google |
Solved |
C++ |
188 |
Array of functions |
Google |
Solved |
C++ |
189 |
Longest contiguous distinct subarray |
Google |
Solved |
C++ |
190 |
Max sum subarray of circular array |
Facebook |
Solved |
C++ |
191 |
Min intervals to remove to make them non-overlapping |
Stripe |
Solved |
C++ |
192 |
Try to reach end of array with array value-sized hops |
Google |
|
|
193 |
Max profit in a stock price array with a fixed transaction fee |
Affirm |
|
|
194 |
Number of intersections between line segments joining two sets of n points of parallel lines |
Facebook |
Solved |
C++ |
195 |
Count elements between two numbers in a 2-D array |
Google |
Solved |
C++ |
196 |
Most frequent subtree sum |
Apple |
Solved |
C++ |
197 |
Rotate array to the right by K in-place |
Amazon |
Solved |
C++ |
198 |
Largest set of non-coprime numbers in a set |
Google |
Solved |
C++ |
199 |
Balanced parantheses - III |
Facebook |
|
|
200 |
Find a stabbing point between n intervals |
Microsoft |
|
|
201 |
Maximum sum path in a triangular array |
Google |
|
|
202 |
Integer palindrome |
Palantir |
Solved |
C++ |
203 |
Minimum element in rotated sorted array in faster than linear time |
Uber |
Solved |
C++ |
204 |
Count the number of nodes in a complete binary tree in faster than linear time |
Amazon |
Solved |
C++ |
205 |
Given a number find the next permutation of it |
IBM |
Solved |
C++ |
206 |
Apply a permutation on an array |
Twitter |
Solved |
C++ |
207 |
Check if a graph is bipartite |
Dropbox |
|
|
208 |
Partition a linked list by a node such that all elements >= a node come after those smaller |
LinkedIn |
Solved |
C++ |
209 |
Longest common subsequence of 3 strings |
YouTube |
|
|
210 |
Collatz conjecture verificity and longest sequence |
Apple |
Solved |
C++ |
211 |
All starting positions of a pattern in a string |
Microsoft |
Solved |
C++ |
212 |
Excel column encoding of a positive integer |
Dropbox |
Solved |
C++ |
213 |
Valid IP address combinations from a string |
Snapchat |
Solved |
C++ |
214 |
Max continuous ones in binary representation of a number |
Stripe |
Solved |
C++ |
|
|
|
|
|
291 |
Minimum boats to rescue |
Glassdoor |
Solved |
C++ |
|
|
|
|
|
294 |
Min Running Track Path |
Square |
Solved |
C++ |
295 |
Pascal's Triangle |
Stitch Fix |
Solved |
C++ |
296 |
Convert sorted array to Balanced BST |
Etsy |
Solved |
C++ |
297 |
Minimum drinks to satisfy preferences |
Amazon |
Solved |
C++ |
298 |
Max Run with at most two discrete elements |
Google |
Solved |
C++ |
299 |
Min pipe length required for a city graph |
Samsung |
Solved |
C++ |
|
|
|
|
|
311 |
Peak element in array in O(log N) time |
Sumo Logic |
Solved |
C++ |