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