big-o-master
- ruby
  - src
    - lists
      - singly_linked_list.rb
    - sorting
      - heap_sort.rb
      - stupid_sort.rb
      - quick_sort.rb
      - merge_sort.rb
    - common
      - array_utils.rb
    - arrays
      - sub_array_with_max_sum.rb
      - sort_012.rb
    - general
      - num_hops.rb
      - longest_palindromic_substring.rb
    - binary_trees
      - tree_node.rb
      - tree_to_circular_list.rb
  - spec
    - lists
      - singly_linked_list_spec.rb
    - sorting
      - quick_sort_spec.rb
      - heap_sort_spec.rb
      - merge_sort_spec.rb
      - stupid_sort_spec.rb
    - .gitkeep
    - arrays
      - sort_012_spec.rb
      - sub_array_with_max_sum_spec.rb
    - binary_trees
      - tree_to_circular_list_spec.rb
    - spec_helper.rb
  - .idea
    - modules.xml
    - encodings.xml
    - .name
    - misc.xml
    - ruby.iml
    - scopes
      - scope_settings.xml
    - workspace.xml
    - vcs.xml
- LICENSE
- DISCLAIMER
- java
  - src
    - graphs
      - SpellChecker.java
      - SearchingTechniques.java
      - GraphNode.java
      - BloodRelatives.java
      - SocialNetworkConnectivity.java
    - trees
      - NaryTreeSerialization.java
      - SumTree.java
      - NaryTreeNode.java
    - binarytrees
      - BstMinValue.java
      - TreeNode.java
      - TreeConvertToSinglyLinkedList.java
      - BstClosestNode.java
      - BstInsert.java
      - BstDoubleTree.java
      - TreeDepth.java
      - BstIsBst.java
      - TreeRecursiveTraversals.java
      - BstCountTrees.java
      - TreeSameTree.java
      - BstLookup.java
      - TreeMirror.java
      - TreeHasPathSum.java
      - TreePrintPaths.java
      - TreeNonRecursiveTraversals.java
      - TreeReconstruct.java
      - TreeSize.java
      - BstFindMode.java
    - sorting
      - KwayMerge.java
      - InsertionSort.java
      - FindMinLengthUnsortedSubArray.java
      - StupidSort.java
      - MergeSort.java
      - Heap.java
      - Sort012.java
      - HeapSort.java
      - QuickSort.java
      - MergeWithSpaceForOtherArray.java
      - SimpleHeapImpl.java
    - bitsandbytes
      - NumSetBits.java
    - common
      - NumberUtils.java
      - Pair.java
      - ListUtils.java
      - ArrayUtils.java
      - BitUtils.java
    - concurrency
      - FirstReadWriteLock.java
      - BoundedBlockingQueue.java
      - ReadWriteLock.java
      - SecondReadWriteLock.java
      - SimpleSchedulingExecutor.java
      - SchedulingExecutor.java
      - Semaphore.java
    - strings
      - RegexMatching.java
      - CheckInterleavedStrings.java
      - LongestSubstringWithNoRepetition.java
      - StringSerialization.java
      - NaivePatternMatching.java
      - LongestPalindromicSubstring.java
      - SentenceReverse.java
    - arrays
      - RearrangeInputToTarget.java
      - Answer0toKRangeQuery.java
      - SimplePhoneNumberAllotter.java
      - FindNumHops.java
      - SearchBitonicArray.java
      - FindCommonElements.java
      - CountInversions.java
      - BoundedQueue.java
    - dp
      - RetrieveSentenceWithShuffledWords.java
      - RatInAMaze.java
      - EditDistance.java
      - RobotMove.java
      - PrintNeatly.java
      - LongestCommonSubsequence.java
      - CountBinarySubsequences.java
    - collections
      - LevelOrderIterator.java
      - PeekIterator.java
      - FilteringIterator.java
      - InorderIterator.java
      - MaxIterator.java
      - HoppingIterator.java
      - RotatingIterator.java
      - MultiIterator.java
      - DeepIterator.java
      - PreorderIterator.java
    - general
      - PowerFunctions.java
      - NumEvenSumPairs.java
      - DigitSerializedArray.java
      - ThreeSum.java
      - Shuffle.java
      - PermutationsCombinations.java
      - PascalsTriangle.java
      - EnglishKeyboard.java
      - SkylineOfACity.java
      - MergeIntervals.java
      - RatInAMaze.java
      - RomanNumerals.java
      - PrimeFactors.java
      - NumberOfZerosInFactorial.java
      - NextPalindromeNumber.java
      - TwoSum.java
      - TwoDifference.java
      - MatrixRegionSum.java
      - Time.java
      - BinaryGap.java
      - NQueens.java
      - MeetingRoom.java
      - SubsetSum.java
      - NextLexciographicalPermutation.java
      - MinimumMeetingRooms.java
      - Maze.java
      - MaximalSum.java
      - KnightsTour.java
      - RainWater.java
      - PalindromeNumber.java
      - FindNumCombinations.java
      - LexicographicalRanking.java
      - YoungsTableau.java
      - Schedule.java
    - cache
      - LRUCache.java
      - Cache.java
    - exceptions
      - EmptyHeapException.java
    - linkedlists
      - SinglyLinkedList.java
      - List.java
  - lib
  - .settings
    - org.eclipse.jdt.ui.prefs
    - org.eclipse.jdt.core.prefs
  - tests
    - lists
      - SinglyLinkedListTest.java
    - sorting
      - InsertionSortTest.java
      - SimpleHeapImplTest.java
      - MergeSortTest.java
      - StupidSortTest.java
      - QuickSortTest.java
      - HeapSortTest.java
    - bitsandbytes
      - NumSetBitsTest.java
    - common
      - NumberUtilsTest.java
    - arrays
      - RearrangeInputToTargetTest.java
      - SimplePhoneNumberAllotterTest.java
    - collections
      - DeepIteratorTest.java
      - PeekIteratorTest.java
    - general
      - RainWaterTest.java
    - cache
      - LRUCacheTest.java
    - AllTests.java
    - binarytree
      - BstFindModeTest.java
      - BstClosestNodeTest.java
  - .project
  - .classpath
- README.md
- .idea
  - modules.xml
  - encodings.xml
  - .name
  - misc.xml
  - scopes
    - scope_settings.xml
  - workspace.xml
  - syringe.iml
  - vcs.xml
- .gitignore

Big O

A big collection of data structures and algorithms puzzles. As on May 2013, the repository has roughly 130 problems with solutions.

Solutions are primarily in Java (under java/). Some solutions are in Ruby (under ruby/).

Problem statements are specified as Javadoc at the top of every solution. I have tried to be as descriptive as I can, but if something is not clear then please do let me know! Problems are broadly classified into the following categories which are self explanatory.

Please feel free to contribute!