Bubble sort added.

Author: thewillyhuman

BubbleSort/Bubble.java

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+package BubbleSort;
+
+/**
+ * Bubble sort is a sorting algorithm that is implemented by starting in the
+ * beginning of the array and swapping the first two elements only if the first
+ * element is greater than the second element. This comparison is then moved
+ * onto the next pair and so on and so forth. This is done until the array is
+ * completely sorted. The smaller items slowly “bubble” up to the beginning of
+ * the array.
+ *
+ * @author Guillermo Facundo Colunga.
+ * @version 1
+ * @since 201712120028.
+ * @formatter Oviedo Computing Community Extended.
+ * @param <T> is the type to sort.
+ */
+public class Bubble<T extends Comparable<T>> {
+
+	/**
+	 * Average: O(N^2) Worst: O(N^2) Memory: O(1)
+	 * 
+	 * Sorts the given array of elements by executing bubble sort. That is by
+	 * starting in the beginning of the array and swapping the first two
+	 * elements only if the first element is greater than the second element.
+	 * This comparison is then moved onto the next pair and so on and so forth.
+	 * This is done until the array is completely sorted. The smaller items
+	 * slowly “bubble” up to the beginning of the array.
+	 * 
+	 * @param elements array to be sorted. It is sorted in the same array.
+	 */
+	public void sort( T[] elements ) {
+		for (int i = 1; i < elements.length; i++) { // O(n)
+			for (int j = elements.length - 1; j >= i; j--) { // O(n)
+				if (elements[j - 1].compareTo( elements[j] ) > 0) {
+					T temp = elements[j];
+					elements[j] = elements[j - 1];
+					elements[j - 1] = temp;
+				}
+			}
+		}
+	}
+
+}

BubbleSort/tests/BubbleTest.java

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+package BubbleSort.tests;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import BubbleSort.Bubble;
+
+public class BubbleTest {
+
+	private Integer[] intArr = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 },
+			sortIntArr = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
+
+	private String[] strArr = { "d", "c", "b", "a" },
+			sortStrArr = { "a", "b", "c", "d" };
+
+	private Double[] dblArr = { 1.9, 2.6, Double.MAX_VALUE, 0.00004, Double.MIN_VALUE },
+			sortDblArr = { Double.MIN_VALUE, 0.00004, 1.9, 2.6, Double.MAX_VALUE };
+
+	@Test public void integerSortTest() {
+		new Bubble<Integer>().sort( intArr );
+		assertArrayEquals( sortIntArr, intArr );
+	}
+
+	@Test public void stringSortTest() {
+		new Bubble<String>().sort( strArr );
+		assertArrayEquals( sortStrArr, strArr );
+	}
+	
+	@Test public void doubleSortTest() {
+		new Bubble<Double>().sort( dblArr );
+		assertArrayEquals( sortDblArr, dblArr );
+	}
+
+}