Title	Solution	Practice	Difficulty	Companies	Topics
1. Two Sum	Solution	Solve	Easy	Accenture+29	Array Hash Table
2. Add Two Numbers	Solution	Solve	Medium	Adobe+14	Linked List Math+1
3. Longest Substring Without Repeating Characters	Solution	Solve	Medium	Adobe+20	Hash Table Sliding Window+1
4. Median of Two Sorted Arrays	Solution	Solve	Hard	Accolite+38	Array Binary Search+1
5. Longest Palindromic Substring	Solution	Solve	Medium	Accenture+50	Dynamic Programming String+1
6. Zigzag Conversion	Solution	Solve	Medium	Adobe+2	String
7. Reverse Integer	Solution	Solve	Medium	Adobe+10	Math
8. String to Integer (atoi)	Solution	Solve	Medium	Adobe+8	String
9. Palindrome Number	Solution	Solve	Easy	Accenture+8	Math
10. Regular Expression Matching	Solution	Solve	Hard	Adobe+8	Dynamic Programming Recursion+1
11. Container With Most Water	Solution	Solve	Medium	Adobe+8	Array Greedy+1
12. Integer to Roman	Solution	Solve	Medium	Adobe+8	Hash Table Math+1
13. Roman to Integer	Solution	Solve	Easy	Accenture+18	Hash Table Math+1
14. Longest Common Prefix	Solution	Solve	Easy	Adobe+9	String Trie
15. 3Sum	Solution	Solve	Medium	Adobe+21	Array Sorting+1
16. 3Sum Closest	Solution	Solve	Medium	Adobe+6	Array Sorting+1
17. Letter Combinations of a Phone Number	Solution	Solve	Medium	Airtel+34	Backtracking Hash Table+1
18. 4Sum	Solution	Solve	Medium	Adobe+8	Array Sorting+1
19. Remove Nth Node From End of List	Solution	Solve	Medium	Amazon+7	Linked List Two Pointers
20. Valid Parentheses	Solution	Solve	Easy	Adobe+25	Stack String
21. Merge Two Sorted Lists	Solution	Solve	Easy	Accenture+9	Linked List Recursion
22. Generate Parentheses	Solution	Solve	Medium	Adobe+12	Backtracking Dynamic Programming+1
23. Merge k Sorted Lists	Solution	Solve	Hard	Adobe+17	Divide and Conquer Heap (Priority Queue)+2
24. Swap Nodes in Pairs	Solution	Solve	Medium	Adobe+5	Linked List Recursion
25. Reverse Nodes in k-Group	Solution	Solve	Hard	Amazon+8	Linked List Recursion
26. Remove Duplicates from Sorted Array	Solution	Solve	Easy	Adobe+8	Array Two Pointers
27. Remove Element	Solution	Solve	Easy	Adobe+4	Array Two Pointers
28. Find the Index of the First Occurrence in a String	Solution	Solve	Easy	Amazon+4	String String Matching+1
29. Divide Two Integers	Solution	Solve	Medium	Adobe+6	Bit Manipulation Math
30. Substring with Concatenation of All Words	Solution	Solve	Hard	Amazon+4	Hash Table Sliding Window+1
31. Next Permutation	Solution	Solve	Medium	Adobe+19	Array Two Pointers
32. Longest Valid Parentheses	Solution	Solve	Hard	Amazon+6	Dynamic Programming Stack+1
33. Search in Rotated Sorted Array	Solution	Solve	Medium	Accenture+91	Array Binary Search
34. Find First and Last Position of Element in Sorted Array	Solution	Solve	Medium	Adobe+18	Array Binary Search
35. Search Insert Position	Solution	Solve	Easy	Adobe+8	Array Binary Search
36. Valid Sudoku	Solution	Solve	Medium	Amazon+9	Array Hash Table+1
37. Sudoku Solver	Solution	Solve	Hard	Adobe+11	Array Backtracking+2
38. Count and Say	Solution	Solve	Medium	Adobe+6	String
39. Combination Sum	Solution	Solve	Medium	Adobe+8	Array Backtracking
40. Combination Sum II	Solution	Solve	Medium	Amazon+4	Array Backtracking
41. First Missing Positive	Solution	Solve	Hard	Adobe+7	Array Hash Table
42. Trapping Rain Water	Solution	Solve	Hard	Adobe+21	Array Dynamic Programming+3
43. Multiply Strings	Solution	Solve	Medium	Adobe+5	Math Simulation+1
44. Wildcard Matching	Solution	Solve	Hard	Amazon+5	Dynamic Programming Greedy+2
45. Jump Game II	Solution	Solve	Medium	Adobe+9	Array Dynamic Programming+1
46. Permutations	Solution	Solve	Medium	Accenture+39	Array Backtracking
47. Permutations II	Solution	Solve	Medium	Amazon+1	Array Backtracking
48. Rotate Image	Solution	Solve	Medium	Adobe+9	Array Math+1
49. Group Anagrams	Solution	Solve	Medium	Adobe+23	Array Hash Table+2
50. Pow(x, n)	Solution	Solve	Medium	Adobe+29	Math Recursion

Two Sum

Easy✓ Solution📹 Video

Accenture+29

Array Hash Table

Solve Solution

Add Two Numbers

Medium✓ Solution📹 Video

Adobe+14

Linked List Math Recursion

Solve Solution

Longest Substring Without Repeating Characters

Medium✓ Solution📹 Video

Adobe+20

Hash Table Sliding Window String

Solve Solution

Median of Two Sorted Arrays

Hard✓ Solution📹 Video

Accolite+38

Array Binary Search Divide and Conquer

Solve Solution

Longest Palindromic Substring

Medium✓ Solution📹 Video

Accenture+50

Dynamic Programming String Two Pointers

Solve Solution

Zigzag Conversion

Medium✓ Solution📹 Video

Adobe+2

String

Solve Solution

Reverse Integer

Medium✓ Solution📹 Video

Adobe+10

Math

Solve Solution

String to Integer (atoi)

Medium✓ Solution📹 Video

Adobe+8

String

Solve Solution

Palindrome Number

Easy✓ Solution📹 Video

Accenture+8

Math

Solve Solution

#10

Regular Expression Matching

Hard✓ Solution📹 Video

Adobe+8

Dynamic Programming Recursion String

Solve Solution

#11

Container With Most Water

Medium✓ Solution📹 Video

Adobe+8

Array Greedy Two Pointers

Solve Solution

#12

Integer to Roman

Medium✓ Solution📹 Video

Adobe+8

Hash Table Math String

Solve Solution

#13

Roman to Integer

Easy✓ Solution📹 Video

Accenture+18

Hash Table Math String

Solve Solution

#14

Longest Common Prefix

Easy✓ Solution📹 Video

Adobe+9

String Trie

Solve Solution

#15

3Sum

Medium✓ Solution📹 Video

Adobe+21

Array Sorting Two Pointers

Solve Solution

#16

3Sum Closest

Medium✓ Solution📹 Video

Adobe+6

Array Sorting Two Pointers

Solve Solution

#17

Letter Combinations of a Phone Number

Medium✓ Solution📹 Video

Airtel+34

Backtracking Hash Table String

Solve Solution

#18

4Sum

Medium✓ Solution📹 Video

Adobe+8

Array Sorting Two Pointers

Solve Solution

#19

Remove Nth Node From End of List

Medium✓ Solution📹 Video

Amazon+7

Linked List Two Pointers

Solve Solution

#20

Valid Parentheses

Easy✓ Solution📹 Video

Adobe+25

Stack String

Solve Solution

#21

Merge Two Sorted Lists

Easy✓ Solution📹 Video

Accenture+9

Linked List Recursion

Solve Solution

#22

Generate Parentheses

Medium✓ Solution📹 Video

Adobe+12

Backtracking Dynamic Programming String

Solve Solution

#23

Merge k Sorted Lists

Hard✓ Solution📹 Video

Adobe+17

Divide and Conquer Heap (Priority Queue)Linked List+1

Solve Solution

#24

Swap Nodes in Pairs

Medium✓ Solution📹 Video

Adobe+5

Linked List Recursion

Solve Solution

#25

Reverse Nodes in k-Group

Hard✓ Solution📹 Video

Amazon+8

Linked List Recursion

Solve Solution

#26

Remove Duplicates from Sorted Array

Easy✓ Solution📹 Video

Adobe+8

Array Two Pointers

Solve Solution

#27

Remove Element

Easy✓ Solution📹 Video

Adobe+4

Array Two Pointers

Solve Solution

#28

Find the Index of the First Occurrence in a String

Easy✓ Solution📹 Video

Amazon+4

String String Matching Two Pointers

Solve Solution

#29

Divide Two Integers

Medium✓ Solution📹 Video

Adobe+6

Bit Manipulation Math

Solve Solution

#30

Substring with Concatenation of All Words

Hard✓ Solution📹 Video

Amazon+4

Hash Table Sliding Window String

Solve Solution

#31

Next Permutation

Medium✓ Solution📹 Video

Adobe+19

Array Two Pointers

Solve Solution

#32

Longest Valid Parentheses

Hard✓ Solution📹 Video

Amazon+6

Dynamic Programming Stack String

Solve Solution

#33

Search in Rotated Sorted Array

Medium✓ Solution📹 Video

Accenture+91

Array Binary Search

Solve Solution

#34

Find First and Last Position of Element in Sorted Array

Medium✓ Solution📹 Video

Adobe+18

Array Binary Search

Solve Solution

#35

Search Insert Position

Easy✓ Solution📹 Video

Adobe+8

Array Binary Search

Solve Solution

#36

Valid Sudoku

Medium✓ Solution📹 Video

Amazon+9

Array Hash Table Matrix

Solve Solution

#37

Sudoku Solver

Hard✓ Solution📹 Video

Adobe+11

Array Backtracking Hash Table+1

Solve Solution

#38

Count and Say

Medium✓ Solution📹 Video

Adobe+6

String

Solve Solution

#39

Combination Sum

Medium✓ Solution📹 Video

Adobe+8

Array Backtracking

Solve Solution

#40

Combination Sum II

Medium✓ Solution📹 Video

Amazon+4

Array Backtracking

Solve Solution

#41

First Missing Positive

Hard✓ Solution📹 Video

Adobe+7

Array Hash Table

Solve Solution

#42

Trapping Rain Water

Hard✓ Solution📹 Video

Adobe+21

Array Dynamic Programming Monotonic Stack+2

Solve Solution

#43

Multiply Strings

Medium✓ Solution📹 Video

Adobe+5

Math Simulation String

Solve Solution

#44

Wildcard Matching

Hard✓ Solution📹 Video

Amazon+5

Dynamic Programming Greedy Recursion+1

Solve Solution

#45

Jump Game II

Medium✓ Solution📹 Video

Adobe+9

Array Dynamic Programming Greedy

Solve Solution

#46

Permutations

Medium✓ Solution📹 Video

Accenture+39

Array Backtracking

Solve Solution

#47

Permutations II

Medium✓ Solution📹 Video

Amazon+1

Array Backtracking

Solve Solution

#48

Rotate Image

Medium✓ Solution📹 Video

Adobe+9

Array Math Matrix

Solve Solution

#49

Group Anagrams

Medium✓ Solution📹 Video

Adobe+23

Array Hash Table Sorting+1

Solve Solution

#50

Pow(x, n)

Medium✓ Solution📹 Video

Adobe+29

Math Recursion

Solve Solution

1 2 3……66 67 68

Page 1 of 68

Problems

3,374+ problems · 840 Easy · 1762 Medium · 772 Hard

Title	Solution	Practice	Difficulty	Companies	Topics
1. Two Sum	Solution	Solve	Easy	Accenture+29	Array Hash Table
2. Add Two Numbers	Solution	Solve	Medium	Adobe+14	Linked List Math+1
3. Longest Substring Without Repeating Characters	Solution	Solve	Medium	Adobe+20	Hash Table Sliding Window+1
4. Median of Two Sorted Arrays	Solution	Solve	Hard	Accolite+38	Array Binary Search+1
5. Longest Palindromic Substring	Solution	Solve	Medium	Accenture+50	Dynamic Programming String+1
6. Zigzag Conversion	Solution	Solve	Medium	Adobe+2	String
7. Reverse Integer	Solution	Solve	Medium	Adobe+10	Math
8. String to Integer (atoi)	Solution	Solve	Medium	Adobe+8	String
9. Palindrome Number	Solution	Solve	Easy	Accenture+8	Math
10. Regular Expression Matching	Solution	Solve	Hard	Adobe+8	Dynamic Programming Recursion+1
11. Container With Most Water	Solution	Solve	Medium	Adobe+8	Array Greedy+1
12. Integer to Roman	Solution	Solve	Medium	Adobe+8	Hash Table Math+1
13. Roman to Integer	Solution	Solve	Easy	Accenture+18	Hash Table Math+1
14. Longest Common Prefix	Solution	Solve	Easy	Adobe+9	String Trie
15. 3Sum	Solution	Solve	Medium	Adobe+21	Array Sorting+1
16. 3Sum Closest	Solution	Solve	Medium	Adobe+6	Array Sorting+1
17. Letter Combinations of a Phone Number	Solution	Solve	Medium	Airtel+34	Backtracking Hash Table+1
18. 4Sum	Solution	Solve	Medium	Adobe+8	Array Sorting+1
19. Remove Nth Node From End of List	Solution	Solve	Medium	Amazon+7	Linked List Two Pointers
20. Valid Parentheses	Solution	Solve	Easy	Adobe+25	Stack String
21. Merge Two Sorted Lists	Solution	Solve	Easy	Accenture+9	Linked List Recursion
22. Generate Parentheses	Solution	Solve	Medium	Adobe+12	Backtracking Dynamic Programming+1
23. Merge k Sorted Lists	Solution	Solve	Hard	Adobe+17	Divide and Conquer Heap (Priority Queue)+2
24. Swap Nodes in Pairs	Solution	Solve	Medium	Adobe+5	Linked List Recursion
25. Reverse Nodes in k-Group	Solution	Solve	Hard	Amazon+8	Linked List Recursion
26. Remove Duplicates from Sorted Array	Solution	Solve	Easy	Adobe+8	Array Two Pointers
27. Remove Element	Solution	Solve	Easy	Adobe+4	Array Two Pointers
28. Find the Index of the First Occurrence in a String	Solution	Solve	Easy	Amazon+4	String String Matching+1
29. Divide Two Integers	Solution	Solve	Medium	Adobe+6	Bit Manipulation Math
30. Substring with Concatenation of All Words	Solution	Solve	Hard	Amazon+4	Hash Table Sliding Window+1
31. Next Permutation	Solution	Solve	Medium	Adobe+19	Array Two Pointers
32. Longest Valid Parentheses	Solution	Solve	Hard	Amazon+6	Dynamic Programming Stack+1
33. Search in Rotated Sorted Array	Solution	Solve	Medium	Accenture+91	Array Binary Search
34. Find First and Last Position of Element in Sorted Array	Solution	Solve	Medium	Adobe+18	Array Binary Search
35. Search Insert Position	Solution	Solve	Easy	Adobe+8	Array Binary Search
36. Valid Sudoku	Solution	Solve	Medium	Amazon+9	Array Hash Table+1
37. Sudoku Solver	Solution	Solve	Hard	Adobe+11	Array Backtracking+2
38. Count and Say	Solution	Solve	Medium	Adobe+6	String
39. Combination Sum	Solution	Solve	Medium	Adobe+8	Array Backtracking
40. Combination Sum II	Solution	Solve	Medium	Amazon+4	Array Backtracking
41. First Missing Positive	Solution	Solve	Hard	Adobe+7	Array Hash Table
42. Trapping Rain Water	Solution	Solve	Hard	Adobe+21	Array Dynamic Programming+3
43. Multiply Strings	Solution	Solve	Medium	Adobe+5	Math Simulation+1
44. Wildcard Matching	Solution	Solve	Hard	Amazon+5	Dynamic Programming Greedy+2
45. Jump Game II	Solution	Solve	Medium	Adobe+9	Array Dynamic Programming+1
46. Permutations	Solution	Solve	Medium	Accenture+39	Array Backtracking
47. Permutations II	Solution	Solve	Medium	Amazon+1	Array Backtracking
48. Rotate Image	Solution	Solve	Medium	Adobe+9	Array Math+1
49. Group Anagrams	Solution	Solve	Medium	Adobe+23	Array Hash Table+2
50. Pow(x, n)	Solution	Solve	Medium	Adobe+29	Math Recursion