Algorithms and Data Structures

Repository for storing Java implemetations of popular algorithms and data structures.

Caesar.java

The Caesar Cipher takes in a String and an Integer key and produces a String that is shifted a certain number down the alphabet.

System.out.println(caesarMethod("Hello World!", 3));

results in

Khoor Zruog!

SymmetricDifference.java

The symmetric difference algorithm takes in two arrays and returns an array containing only the difference.

Integer[] firstArray = {2, 2, 3, 4, 5};
Integer[] secondArray = {2, 4, 6, 8, 10};
SymmetricDifference.getSymmetricDifference(firstArray, secondArray);

results in

[3, 5, 6, 8, 10]

RotateArray.java

The rotate array algorithm rotates an array to the right by a given key.

Integer[] intArray = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};            
int key = 3;                                                     
System.out.println(Arrays.toString(rotateArray(intArray, key))); 

results in

[8, 9, 10, 1, 2, 3, 4, 5, 6, 7]

ReverseWordsInAString.java

Algorithm to reverse the words in a string.

String input = "Hello to the entire world!";
System.out.println(reverser(input));

results in

world! entire the to Hello 

BinarySearch.java

Algorithm using a recursive function to efficiently search through an ordered array.

int IntToSearchFor = 33;
binarySearch(myArray, IntToSearchFor, myArray.length - 1, 0);

results in

The index of the missing number is: 33

RepeatingNumbers.java

Utilizes a HashMap to return the only number in an Array that repeats an odd number of times.

int[] myArray = {1, 2, 6, 2, 1};
System.out.println(repeatingNumber(myArray));

results in

6

MultithreadingSearch.java

Utilizes multiple threads to quickly search an array for an integer.

int[] myArray = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int numberToFind = 10;
threadCreation(myArray, 2, false, numberToFind);

results in

Thread 1 thread can't find your missing number!
Found = false
Thread 2 thread found the number: 10
Found = true

###DijkstrasShortestPath.java

Still in progress

Utilizing OOP and HashSets to find the shortest path in a graph

###RemoveDups.java

Algorithm for removing duplicates from a linked list.

 Node startNode = new Node(1);
 startNode.appendToTail(2);
 startNode.appendToTail(3);
 startNode.appendToTail(1);
 startNode.appendToTail(2);
 RemoveDups removeDups = new RemoveDups(); 
 removeDups.remove(startNode);

results in

1
2
3