Recursion

1. Generate all combination of size k and less of adjacent numbers - AllAdjacentCombination.java
2. Generate all bracket combination, check if brackets open and closing is correct or not - Bracketology.java
3. Given an array of strings, find if the given strings can be chained to form a circle. A string X can be put before another string Y in circle if the last character of X is same as first character of Y - ChainWordsToFormCircle.java
4. Generate all combinations - Combination.java
5. Generate all combination of size k - CombinationOfSizeK.java
6. Generate all combination which prints star in place of absent characters - CombinationWithStar.java
7. Consider a coding system for alphabets to integers where ‘a’ is represented as 1, ‘b’ as 2, .. ‘z’ as 26. Given an array of digits (1 to 9) as input, write a function that prints all valid interpretations of input array - InterpretationOfArray.java
8. Generate all possible string combinations of a given phone number - KeyPadPermutation.java
9. Minimum edits required to generate reverse polish notation - MinimumEditForReversePolishNotation.java
10. Given a board of size nxn and n queens, place them on the board so that they don't attack each other - NQueenProblem.java
11. Given two strings check if they are one distance away from each other where you can delete,edit or add characters - OneEditApart.java
12. Print all paths from top left corner to bottom right corner - PrintAllPathFromTopLeftToBottomRight.java
13. Given an array find number of interpretations possible for combinations of adjacent characters - PrintArrayInAdjacentWay.java
14. Print array in tree fashion - PrintArrayInCustomizedFormat.java
15. Permutation of string in both sorted and unsorted order - StringPermutation.java stringpermutation.py StringPermutationRotation.java
16. Given two strings, generate all interleavings of these strings - StringInterleaving.java
17. Shuffle a character array so that no two repeated characters are together. [FancyShuffle.java] (https://github.com/mission-peace/interview/blob/master/src/com/interview/recursion/FancyShuffle.java)
18. Given an input and total, print all combinations with repetitions in this input which sums to given total. PrintSumCombination.java
19. Given a List of List of Strings. Print cartesian product of List. WordCombination.java
20. Given input of unique elements and pair among those elements. How many minimum swaps are needed to arrange pair adjacent to each other. SetPairTogether.java setpairtogether.py
21. Given input string e.g 123 and target e.g 6, place operator +, - and * so that 123 evaluates to 6. OperatorAdditionForTarget.java
22. Print all permutations of given input array - PrintAllSubsequence.java
23. Reconstruct itinerary based on ticket - ReconstructItinerary.java
24. Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results - RemoveInvalidParenthesis.java
25. Sudoku solver - SudokuSolver.java
26. Restore ip address - RestoreIPAddresses.java
27. Find absolute longest path in directory structure represented by \n and \t - LongestAbsolutePath.java