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