Practice Data Structures & Algorithms in Java

Data Structures & Algorithms exercises

1. Two Sum (Sorted Array) Java exercise — Find two numbers in a sorted array that add up to target
2. Remove Duplicates from Sorted Array Java exercise — Remove duplicates in-place and return new length
3. Container With Most Water Java exercise — Find two lines that form container with most water
4. Three Sum Java exercise — Find all unique triplets that sum to zero
5. Valid Palindrome Java exercise — Check if string is palindrome considering only alphanumeric
6. Maximum Sum Subarray of Size K Java exercise — Find maximum sum of any contiguous subarray of size k
7. Longest Substring with K Distinct Characters Java exercise — Find longest substring with at most k distinct characters
8. Minimum Window Substring Java exercise — Find minimum window containing all characters of pattern
9. Longest Repeating Character Replacement Java exercise — Longest substring with same letter after k replacements
10. Fruit Into Baskets Java exercise — Maximum fruits you can collect with two baskets
11. Fibonacci with DP Java exercise — Calculate nth Fibonacci number efficiently
12. Climbing Stairs Java exercise — Count distinct ways to climb n stairs (1 or 2 steps)
13. House Robber Java exercise — Maximum money without robbing adjacent houses
14. Coin Change Java exercise — Minimum coins needed to make amount
15. Longest Increasing Subsequence Java exercise — Find length of longest strictly increasing subsequence
16. 0/1 Knapsack Java exercise — Maximum value with limited weight capacity
17. Unique Paths in Grid Java exercise — Count paths from top-left to bottom-right
18. Longest Common Subsequence Java exercise — Find length of longest common subsequence of two strings
19. Edit Distance (Levenshtein) Java exercise — Minimum operations to convert one string to another
20. Maximum Subarray (Kadane's Algorithm) Java exercise — Find contiguous subarray with largest sum
21. Two Sum (Unsorted) Java exercise — Find two numbers that add up to target using HashMap
22. Group Anagrams Java exercise — Group strings that are anagrams of each other
23. Subarray Sum Equals K Java exercise — Count subarrays with sum equal to k
24. Longest Consecutive Sequence Java exercise — Find length of longest consecutive elements sequence
25. Valid Anagram Java exercise — Check if two strings are anagrams
26. Valid Parentheses Java exercise — Check if parentheses string is valid
27. Next Greater Element Java exercise — Find next greater element for each array element
28. Daily Temperatures Java exercise — Days until warmer temperature
29. Largest Rectangle in Histogram Java exercise — Find largest rectangular area in histogram
30. Min Stack Java exercise — Design stack that supports getMin in O(1)
31. Binary Tree Inorder Traversal Java exercise — Traverse tree in Left-Root-Right order
32. Maximum Depth of Binary Tree Java exercise — Find the maximum depth (height) of a binary tree
33. Binary Tree Level Order Traversal Java exercise — Traverse tree level by level (BFS)
34. Validate Binary Search Tree Java exercise — Check if a binary tree is a valid BST
35. Lowest Common Ancestor Java exercise — Find lowest common ancestor of two nodes
36. Number of Islands Java exercise — Count number of islands in a 2D grid
37. Clone Graph Java exercise — Create a deep copy of an undirected graph
38. Course Schedule (Cycle Detection) Java exercise — Check if all courses can be finished
39. Word Ladder (Shortest Path) Java exercise — Find shortest transformation sequence
40. Rotting Oranges (Multi-source BFS) Java exercise — Minimum time for all oranges to rot
41. Jump Game Java exercise — Can you reach the last index?
42. Activity Selection (Interval Scheduling) Java exercise — Select maximum non-overlapping activities
43. Gas Station Java exercise — Find starting station to complete circuit
44. Partition Labels Java exercise — Partition string so each letter appears in at most one part
45. Task Scheduler Java exercise — Minimum time to complete all tasks with cooldown
46. Binary Search Java exercise — Find target in sorted array
47. Search in Rotated Sorted Array Java exercise — Binary search in rotated array
48. Find Minimum in Rotated Sorted Array Java exercise — Find the minimum element in rotated array
49. Koko Eating Bananas Java exercise — Minimum eating speed to finish in h hours
50. Capacity To Ship Packages Java exercise — Minimum ship capacity to ship all in D days
51. Subsets (Power Set) Java exercise — Generate all subsets of a set
52. Permutations Java exercise — Generate all permutations of an array
53. Combination Sum Java exercise — Find combinations that sum to target
54. N-Queens Java exercise — Place N queens on NxN board with no attacks
55. Word Search Java exercise — Find if word exists in grid
56. Kth Largest Element Java exercise — Find the kth largest element in array
57. Merge K Sorted Lists Java exercise — Merge k sorted linked lists
58. Top K Frequent Elements Java exercise — Find k most frequent elements
59. Find Median from Data Stream Java exercise — Track median as numbers are added
60. Meeting Rooms II Java exercise — Minimum number of conference rooms required