# Problem Code Type Topic Companies Average Time Score
1 Combination Sum code Backtracking
AmazonAdobe
52:13 300
2 Combination Sum II code Backtracking
AmazonInfosys
34:26 300
3 Combinations code Backtracking
AmazonAdobe
38:18 300
4 Generate all Parentheses II code Backtracking
44:12 350
5 Gray Code code Backtracking
49:35 350
6 Kth Permutation Sequence code Backtracking
Amazon
69:59 350
7 Letter Phone code Backtracking
Epic systems
46:50 250
8 NQueens code Backtracking
QualcommAmazon
62:44 550
9 Palindrome Partitioning code Backtracking
Amazon
57:34 300
10 Permutations code Backtracking
Adobe
34:25 350
11 Subset code Backtracking
Amazon
53:53 250
12 Subsets II code Backtracking
Amazon
33:28 300
13 Sudoku code Backtracking
Qualcomm
56:27 700
14 Array and Prime Divisors New code Codersbit
29:29 150
15 Delete and Conquer New code Codersbit
12:28 150
16 Distinct Primes New code Codersbit
31:31 150
17 EZPZ New code Codersbit
34:45 200
18 Going back to OS New objective Codersbit
15:16 30
19 Longest Subarray Difference code Codersbit
72:18 200
20 MinimiZe New code Codersbit
30:04 200
21 Shortest Path in Simple Graph New objective Codersbit
3:56 30
22 Smallest Subarray New code Codersbit
34:51 250
23 The Sequence game New code Codersbit
23:49 200
24 Three Numbers code Codersbit
48:56 200
25 Try some SQL New objective Codersbit
10:28 30
26 Vowels code Codersbit
60:47 250
27 2-Sum Binary Tree code Tree Data Structure
Amazon
53:04 400
28 Balanced Binary Tree code Tree Data Structure
Amazon
27:22 275
29 Binary Tree From Inorder And Postorder code Tree Data Structure
Amazon
39:18 375
30 BST Iterator code Tree Data Structure
Amazon
34:15 500
31 Construct Binary Tree From Inorder And Preorder code Tree Data Structure
Amazon
39:03 375
32 Flatten Binary Tree to Linked List code Tree Data Structure
AdobeAmazon
37:33 500
33 Hotel Reviews code Tree Data Structure
Booking.com
66:18 200
34 Identical Binary Trees code Tree Data Structure
Amazon
10:42 300
35 Inorder Traversal code Tree Data Structure
Amazon
29:37 350
36 Inorder Traversal of Cartesian Tree code Tree Data Structure
Amazon
41:38 300
37 Invert the Binary Tree code Tree Data Structure
11:41 300
38 Kth Smallest Element In Tree code Tree Data Structure
Amazon
26:13 300
39 Least Common Ancestor code Tree Data Structure
AdobeAmazon
51:15 450
40 Max Depth of Binary Tree code Tree Data Structure
Goldman SachsBloomberg
6:14 350
41 Min Depth of Binary Tree code Tree Data Structure
Amazon
15:54 350
42 Order of People Heights code Tree Data Structure
65:01 700
43 Path Sum code Tree Data Structure
Amazon
24:17 350
44 Populate Next Right Pointers Tree code Tree Data Structure
Amazon
42:39 900
45 Postorder Traversal code Tree Data Structure
Amazon
27:06 350
46 Preorder Traversal code Tree Data Structure
Amazon
13:37 350
47 Recover Binary Search Tree code Tree Data Structure
48:59 750
48 Root to Leaf Paths With Sum code Tree Data Structure
Amazon
35:41 350
49 Shortest Unique Prefix code Tree Data Structure
60:27 350
50 Sorted Array To Balanced BST code Tree Data Structure
VMWareAmazon
25:23 300
51 Sum Root to Leaf Numbers code Tree Data Structure
39:39 350
52 Symmetric Binary Tree code Tree Data Structure
Amazon
19:47 300
53 Vertical Order traversal of Binary Tree code Tree Data Structure
Amazon
61:03 200
54 ZigZag Level Order Traversal BT code Tree Data Structure
Amazon
37:42 350
55 Evaluate Expression code Stacks And Queues
30:44 400
56 Largest Rectangle in Histogram code Stacks And Queues
55:05 450
57 Min Stack code Stacks And Queues
AmazonAdobe
40:03 400
58 Nearest Smaller Element code Stacks And Queues
Amazon
38:55 350
59 Rain Water Trapped code Stacks And Queues
QualcommAmazon
51:13 400
60 Redundant Braces code Stacks And Queues
Amazon
39:30 300
61 Simplify Directory Path code Stacks And Queues
48:05 250
62 Sliding Window Maximum code Stacks And Queues
ChronusWalmart labs
58:29 450
63 Add Binary Strings code Strings
37:21 300
64 Atoi code Strings
AdobeNvidiaAgilent systemsBloombergAmazonGroupon
48:12 250
65 Compare Version Numbers code Strings
IntuitAmazon
58:28 225
66 Count And Say code Strings
39:10 250
67 Implement StrStr code Strings
AmazonQualcommWipro
31:35 225
68 Integer To Roman code Strings
Amazon
37:16 250
69 Justified Text code Strings
69:26 300
70 Length of Last Word code Strings
Amazon
17:35 225
71 Longest Common Prefix code Strings
26:05 225
72 Longest Palindromic Substring code Strings
AmazonGroupon
53:55 500
73 Minimum Characters required to make a String Palindromic code Strings
55:27 200
74 Multiply Strings code Strings
53:29 375
75 Palindrome String code Strings
29:56 150
76 Power of 2 code Strings
Amazon
54:03 350
77 Pretty Json code Strings
55:06 400
78 Reverse the String code Strings
QualcommAmazonCisco
35:21 250
79 Roman To Integer code Strings
Amazon
30:34 250
80 Valid Ip Addresses code Strings
Amazon
52:25 250
81 Valid Number code Strings
Adobe
51:38 250
82 Zigzag String code Strings
47:30 300
83 Convert Integer To Roman Number shell Regex and Functions
27:38 400
84 Sort by Frequency shell Regex and Functions
52:19 250
85 Swap Forward And Backward Slash shell Regex and Functions
16:29 200
86 Valid Email Address shell Regex and Functions
27:15 350
87 Add Two Numbers as Lists code Linked Lists
AmazonQualcomm
40:18 250
88 Insertion Sort List code Linked Lists
42:00 300
89 K reverse linked list code Linked Lists
48:57 200
90 List Cycle code Linked Lists
AmazonNetApp
37:10 600
91 Merge Two Sorted Lists code Linked Lists
26:41 300
92 Palindrome List code Linked Lists
Amazon
43:50 200
93 Partition List code Linked Lists
44:18 275
94 Remove Duplicates from Sorted List code Linked Lists
VMWare
16:43 300
95 Remove Duplicates from Sorted List II code Linked Lists
VMWare
51:19 300
96 Remove Nth Node from List End code Linked Lists
HCLAmazon
25:41 350
97 Reorder List code Linked Lists
Amazon
51:45 600
98 Reverse Link List II code Linked Lists
Amazon
54:12 450
99 Rotate List code Linked Lists
Amazon
30:40 350
100 Sort List code Linked Lists
47:46 350
101 Swap List Nodes in pairs code Linked Lists
30:19 350
102 Arrange II code Dynamic Programming
Amazon
70:43 350
103 Best Time to Buy and Sell Stocks I code Dynamic Programming
Amazon
24:36 300
104 Best Time to Buy and Sell Stocks II code Dynamic Programming
Amazon
33:49 225
105 Best Time to Buy and Sell Stocks III code Dynamic Programming
Amazon
45:24 700
106 Coin Sum Infinite code Dynamic Programming
53:07 225
107 Coins in a Line code Dynamic Programming
50:39 300
108 Count Permutations of BST code Dynamic Programming
80:57 400
109 Distinct Subsequences code Dynamic Programming
48:42 325
110 Dungeon Princess code Dynamic Programming
58:01 300
111 Edit Distance code Dynamic Programming
39:03 300
112 Equal Average Partition code Dynamic Programming
Amazon
85:01 350
113 Evaluate Expression To True code Dynamic Programming
Amazon
66:50 350
114 Flip Array code Dynamic Programming
81:07 200
115 Interleaving Strings code Dynamic Programming
45:02 500
116 Intersecting Chords in a Circle code Dynamic Programming
57:53 300
117 Jump Game Array code Dynamic Programming
AmazonEbay
34:44 225
118 Kth Manhattan Distance Neighbourhood code Dynamic Programming
Liv.ai
63:40 200
119 Largest area of rectangle with permutations code Dynamic Programming
62:32 200
120 Length of Longest Subsequence code Dynamic Programming
54:51 200
121 Longest Arithmetic Progression code Dynamic Programming
62:21 200
122 Longest Increasing Subsequence code Dynamic Programming
Epic systemsAmazon
26:36 300
123 Longest valid Parentheses code Dynamic Programming
44:47 700
124 Max Product Subarray code Dynamic Programming
Amazon
53:59 300
125 Max Rectangle in Binary Matrix code Dynamic Programming
61:51 350
126 Max Sum Path in Binary Tree code Dynamic Programming
DirectiAmazon
44:56 400
127 Max Sum Without Adjacent Elements code Dynamic Programming
Epic systems
49:07 225
128 Min Jumps Array code Dynamic Programming
AmazonEbay
56:28 300
129 Min Sum Path in Matrix code Dynamic Programming
Amazon
26:28 300
130 Min Sum Path in Triangle code Dynamic Programming
36:34 300
131 N digit numbers with digit sum S code Dynamic Programming
57:24 200
132 Palindrome Partitioning II code Dynamic Programming
Amazon
45:06 400
133 Queen Attack code Dynamic Programming
76:49 350
134 Regular Expression II code Dynamic Programming
58:01 500
135 Regular Expression Match code Dynamic Programming
62:22 500
136 Repeating Sub-Sequence code Dynamic Programming
50:42 300
137 Rod Cutting code Dynamic Programming
78:00 350
138 Scramble String code Dynamic Programming
55:58 500
139 Shortest common superstring code Dynamic Programming
76:13 200
140 Stairs code Dynamic Programming
Morgan StanleyAmazonIntel
13:40 225
141 Sub Matrices with sum Zero code Dynamic Programming
76:04 200
142 Tushar's Birthday Bombs code Dynamic Programming
81:57 200
143 Tushar's Birthday Party code Dynamic Programming
Snapdeal
60:39 200
144 Unique Binary Search Trees II code Dynamic Programming
AmazonSamsung
28:41 400
145 Unique Paths in a Grid code Dynamic Programming
27:51 300
146 Ways to color a 3xN Board code Dynamic Programming
64:13 200
147 Ways to Decode code Dynamic Programming
Amazon
59:56 225
148 Word Break code Dynamic Programming
IBM
51:00 400
149 Word Break II code Dynamic Programming
IBM
54:56 350
150 Design Messenger subjective System Design Interview Questions
AmazonAmazon Lab126
41:40 600
151 Design Search Typeahead subjective System Design Interview Questions
53:20 400
152 Design Twitter subjective System Design Interview Questions
Flipkart
38:20 600
153 Design URL Shortener subjective System Design Interview Questions
AmazonDirectiZenefits
45:00 300
154 Monkeys and Doors objective Puzzles
Amazon
10:09 40
155 Ten Black and White Socks objective Puzzles
3:58 40
156 Daughters' Ages objective Puzzles
11:49 40
157 Breaking Chocolate Bars objective Puzzles
4:58 40
158 Jelly Beans Jars objective Puzzles
6:54 40
159 Medicine Chest on a Boat objective Puzzles
8:18 40
160 Cross the Bridge objective Puzzles
8:09 40
161 Spinning Disc's Direction objective Puzzles
6:16 40
162 Wizards and Drawves objective Puzzles
12:07 40
163 Genie and Hats objective Puzzles
6:55 40
164 Color of the last ball objective Puzzles
4:49 40
165 Arrange Cubes objective Puzzles
14:18 40
166 Equilateral Triangles using Toothpicks objective Puzzles
5:36 40
167 The Tribe objective Puzzles
Amazon
5:46 40
168 Measure Time by Burning Ropes objective Puzzles
6:12 40
169 Dinner Hand Shakes objective Puzzles
6:33 40
170 Helium Balloon objective Puzzles
1:52 40
171 Divide the Cake objective Puzzles
2:55 40
172 Color of the last ball II objective Puzzles
3:03 40
173 Measure Time by Hourglass objective Puzzles
8:10 40
174 Make a Statement objective Puzzles
Oracle
4:05 40
175 Two Pills each day objective Puzzles
3:18 40
176 Find the Defective Ball objective Puzzles
5:52 40
177 Bee Travel objective Puzzles
7:26 40
178 Six Colored Cubes objective Puzzles
11:58 40
179 Prisoners and Poison objective Puzzles
Amazon
15:25 40
180 World Trips objective Puzzles
8:41 40
181 Color of the Bear objective Puzzles
3:26 40
182 Two Numbers objective Puzzles
11:11 40
183 Next Number objective Puzzles
16:22 40
184 One Mile on the Globe objective Puzzles
7:13 40
185 Marbles in Jar objective Puzzles
9:56 40
186 Divide Gold Bar objective Puzzles
Ebay
5:33 40
187 Min Elevator Trips objective Puzzles
18:08 40
188 100 People in a Circle objective Puzzles
10:41 40
189 Gates of Heaven objective Puzzles
7:18 40
190 Fastest Horses objective Puzzles
6:35 40
191 Train Station objective Puzzles
16:57 40
192 Cats and a Square objective Puzzles
6:53 40
193 Good Processor objective Puzzles
7:17 40
194 Quarters on a Table objective Puzzles
4:33 40
195 Blindfolded Coin Toss objective Puzzles
3:03 40
196 Measure Milk by Cans objective Puzzles
Amtel
13:30 40
197 Light Switches in the Cellar objective Puzzles
Amazon
2:50 40
198 Cross the Bridge II objective Puzzles
5:08 40
199 Last Palindromic Date objective Puzzles
10:13 40
200 Fake Note objective Puzzles
4:58 40
201 Find the Defective Ball II objective Puzzles
2:46 40
202 Next Number II objective Puzzles
Amazon
2:54 40
203 Eggs and Building objective Puzzles
Nvidia
11:55 40
204 Celebrity Problem objective Puzzles
7:52 40
205 Ants on a Triangle objective Puzzles
4:33 40
206 Spider's Web objective Puzzles
Bloomberg
3:32 40
207 Ratio of Boys and Girls objective Puzzles
13:22 40
208 Assign Mice to Holes code Greedy Algorithm
Amazon
18:42 300
209 Bulbs code Greedy Algorithm
19:39 200
210 Distribute Candy code Greedy Algorithm
52:27 300
211 Gas Station code Greedy Algorithm
BloombergDE ShawAmazon
47:16 700
212 Highest Product code Greedy Algorithm
CourseraAmazon
26:02 200
213 Majority Element code Greedy Algorithm
16:39 400
214 Seats code Greedy Algorithm
Walmart labs
62:02 300
215 AMORTIZED1 objective Time Complexity
3:03 100
216 CHOOSE1 objective Time Complexity
1:43 50
217 CHOOSE2 objective Time Complexity
2:23 80
218 CHOOSE3 objective Time Complexity
1:39 50
219 CHOOSE4 objective Time Complexity
0:57 50
220 GCD_CMPL objective Time Complexity
4:13 150
221 LOOP_CMPL objective Time Complexity
2:43 20
222 LOOP_CMPL2 objective Time Complexity
2:43 80
223 NESTED_CMPL objective Time Complexity
1:10 20
224 NESTED_CMPL2 objective Time Complexity
1:25 30
225 NESTED_CMPL3 objective Time Complexity
3:56 80
226 REC_CMPL1 objective Time Complexity
6:58 80
227 REC_CMPL2 objective Time Complexity
6:25 80
228 REC_CMPL3 objective Time Complexity
4:39 150
229 WHILE_CMPL objective Time Complexity
1:31 50
230 Diffk code Two Pointers
26:54 300
231 Intersection Of Sorted Arrays code Two Pointers
17:19 225
232 Merge Two Sorted Lists II code Two Pointers
AdobeExpedia
23:19 200
233 3 Sum code Two Pointers
Amazon
54:38 225
234 Remove Duplicates from Sorted Array code Two Pointers
United HealthgroupAmazonExpedia
29:35 250
235 Sort by Color code Two Pointers
20:47 325
236 Array 3 Pointers code Two Pointers
46:57 400
237 Container With Most Water code Two Pointers
42:28 400
238 3 Sum Zero code Two Pointers
47:53 225
239 Remove Duplicates from Sorted Array II code Two Pointers
Expedia
29:01 250
240 Remove Element from Array code Two Pointers
Amazon
25:32 250
241 Max Continuous Series of 1s code Two Pointers
VMWare
68:07 300
242 Counting Triangles code Two Pointers
50:55 225
243 Minimize the absolute difference code Two Pointers
53:23 200
244 Design Cache subjective Storage Scalability
AmazonOla Cabs
40:00 200
245 Highly Available Database subjective Storage Scalability
Amazon
50:00 400
246 Highly Consistent Database subjective Storage Scalability
50:00 400
247 Sharding a Database subjective Storage Scalability
AmazonDropbox
35:00 200
248 Different Bits Sum Pairwise code Bit Manipulation
43:54 300
249 Divide Integers code Bit Manipulation
Amazon
54:55 250
250 Min XOR value code Bit Manipulation
Booking.com
34:53 200
251 Number of 1 Bits code Bit Manipulation
Adobe
8:19 200
252 Reverse Bits code Bit Manipulation
NvidiaHCLAmazon
22:02 225
253 Single Number code Bit Manipulation
Amazon
11:15 275
254 Single Number II code Bit Manipulation
Amazon
35:36 275
255 2 Sum code Hashing
Amazon
43:21 300
256 4 Sum code Hashing
Amazon
55:22 325
257 Anagrams code Hashing
Amazon
41:37 350
258 Colorful Number code Hashing
Epic systems
40:01 150
259 Copy List code Hashing
Amazon
45:38 450
260 Diffk II code Hashing
25:14 375
261 Equal code Hashing
60:35 350
262 Fraction code Hashing
Amazon
68:56 450
263 Largest Continuous Sequence Zero Sum code Hashing
57:11 200
264 Longest Substring Without Repeat code Hashing
Amazon
43:42 350
265 Points on the Straight Line code Hashing
AmazonInMobi
64:20 450
266 Substring Concatenation code Hashing
62:20 1000
267 Valid Sudoku code Hashing
Amazon
42:07 325
268 Window String code Hashing
Directi
67:56 350
269 Actors and their Movies sql SQL Programming
23:02 100
270 Movie Character sql SQL Programming
22:12 100
271 Neutral Reviewers sql SQL Programming
15:46 100
272 Short Films sql SQL Programming
20:52 100
273 Allocate Books code Binary Search
56:04 350
274 Implement Power Function code Binary Search
56:48 275
275 Matrix Median code Binary Search
61:09 225
276 Matrix Search code Binary Search
34:22 250
277 Median of Array code Binary Search
AmazonVMWare
72:11 325
278 Painter's Partition Problem code Binary Search
64:56 350
279 Rotated Sorted Array Search code Binary Search
53:01 325
280 Search for a Range code Binary Search
38:58 250
281 Sorted Insert Position code Binary Search
23:17 250
282 Square Root of Integer code Binary Search
Amazon
39:40 275
283 Black Shapes code Graph Data Structure & Algorithms
Amazon
41:25 300
284 Capture Regions on Board code Graph Data Structure & Algorithms
50:30 500
285 Clone Graph code Graph Data Structure & Algorithms
Amazon
44:50 500
286 Commutable Islands code Graph Data Structure & Algorithms
Amazon
61:46 200
287 Convert Sorted List to Binary Search Tree code Graph Data Structure & Algorithms
34:48 300
288 Knight On Chess Board code Graph Data Structure & Algorithms
Goldman SachsAmazon
54:23 300
289 Largest Distance between nodes of a Tree code Graph Data Structure & Algorithms
64:55 200
290 Level Order code Graph Data Structure & Algorithms
Groupon
25:25 300
291 Possibility of finishing all courses given pre-requisites code Graph Data Structure & Algorithms
Amazon
52:40 200
292 Smallest Multiple With 0 and 1 code Graph Data Structure & Algorithms
Amazon
75:02 300
293 Smallest sequence with given Primes code Graph Data Structure & Algorithms
Booking.com
53:41 200
294 Stepping Numbers code Graph Data Structure & Algorithms
Epic systems
44:09 300
295 Sum Of Fibonacci Numbers code Graph Data Structure & Algorithms
41:40 300
296 Valid Path code Graph Data Structure & Algorithms
Morgan StanleyAmazonCodenation
76:15 200
297 Word Ladder I code Graph Data Structure & Algorithms
Ebay
50:50 600
298 Word Ladder II code Graph Data Structure & Algorithms
Ebay
63:10 800
299 Word Search Board code Graph Data Structure & Algorithms
Epic systemsAmazon
42:01 500
300 Add One To Number code Arrays
43:43 225
301 Anti Diagonals code Arrays
Adobe
38:50 225
302 Find Duplicate in Array code Arrays
AmazonVMWareRiverbed
38:50 450
303 Find Permutation code Arrays
47:36 300
304 First Missing Integer code Arrays
Model NInMobi
63:01 300
305 Flip code Arrays
VMWare
72:00 400
306 Hotel Bookings Possible code Arrays
59:22 225
307 Kth Row of Pascal's Triangle code Arrays
27:28 225
308 Largest Number code Arrays
AmazonGoldman Sachs
69:37 225
309 Max Distance code Arrays
Amazon
62:21 250
310 Max Non Negative SubArray code Arrays
57:42 150
311 Max Sum Contiguous Subarray code Arrays
Amazon
33:39 225
312 Maximum Absolute Difference code Arrays
62:32 250
313 Maximum Consecutive Gap code Arrays
Hunan Asset
50:25 450
314 Maximum Unsorted Subarray code Arrays
56:19 250
315 MAXSPPROD code Arrays
73:29 200
316 Merge Intervals code Arrays
76:54 225
317 Merge Overlapping Intervals code Arrays
44:48 225
318 Min Steps in Infinite Grid code Arrays
Directi
37:51 150
319 N/3 Repeat Number code Arrays
61:20 600
320 Next Permutation code Arrays
Amazon
56:58 300
321 Noble Integer code Arrays
41:02 200
322 Pascal Triangle code Arrays
Amazon
26:16 225
323 Repeat and Missing Number Array code Arrays
Amazon
62:14 350
324 Rotate Matrix code Arrays
Amazon
57:05 300
325 Set Matrix Zeros code Arrays
OracleAmazon
46:24 300
326 Spiral Order Matrix II code Arrays
JP MorganAmazon
45:24 225
327 Triplets with Sum between given range code Arrays
73:49 200
328 Wave Array code Arrays
Adobe
22:01 225
329 Lines in a given range shell Basic Shell Commands
28:54 200
330 Remove Punctuations shell Basic Shell Commands
18:04 250
331 Transform CSV shell Basic Shell Commands
23:03 300
332 Valid phone number shell Basic Shell Commands
20:09 150
333 Excel Column Number code Math
Amazon
23:01 175
334 Excel Column Title code Math
Amazon
38:37 175
335 FizzBuzz code Math
11:54 200
336 Greatest Common Divisor code Math
NetApp
10:44 200
337 Grid Unique Paths code Math
AmazonAdobe
31:53 375
338 Largest Coprime Divisor code Math
43:15 250
339 Numbers of length N and value less than K code Math
82:41 200
340 Palindrome Integer code Math
HCL
17:13 200
341 Power Of Two Integers code Math
HousingAmazon
37:40 250
342 Prime Sum code Math
Epic systems
41:53 150
343 Rearrange Array code Math
47:33 250
344 Reverse integer code Math
HCLBloomberg
27:31 200
345 Sorted Permutation Rank code Math
HousingZenefits
65:58 250
346 Sorted Permutation Rank with Repeats code Math
HousingZenefits
67:02 500
347 Sum of pairwise Hamming Distance code Math
54:42 200
348 Trailing Zeros in Factorial code Math
JabongZillow
18:04 250
349 Distinct Numbers in Window code Heaps And Maps
Amazon
34:23 600
350 LRU Cache code Heaps And Maps
AdobeCitigroupAmazon
61:15 1000
351 Magician and Chocolates code Heaps And Maps
36:01 250
352 Merge K Sorted Lists code Heaps And Maps
FlipkartAmazon
38:04 600
353 N max pair combinations code Heaps And Maps
Liv.ai
75:12 200
354 Ways to form Max Heap code Heaps And Maps
Directi
75:27 200