💡 Add javadoc

Author: kykungz

Sorting/SelectionSort.java

@@ -1,5 +1,21 @@
+/**
+ * Utility class for sorting an array using Selection Sort algorithm. Selection
+ * Sort is a basic algorithm for sorting with O(n^2) time complexity. Basic idea
+ * of this algorithm is to find a local minimum, which is the minimum value from
+ * (i+1) to length of the array [i+1, arr.length), and swap it with the current
+ * working index (i).
+ *
+ * @author Kongpon Charanwattanakit
+ *
+ */
 public class SelectionSort {
 
+	/**
+	 * Sort an array using Selection Sort algorithm.
+	 *
+	 * @param arr
+	 *            is an array to be sorted
+	 */
 	public static void sort(int[] arr) {
 		for (int i = 0; i < arr.length; i++) {
 			int min = i;
@@ -13,6 +29,16 @@ public static void sort(int[] arr) {
 		}
 	}
 
+	/**
+	 * Utility method for swapping elements in an array.
+	 *
+	 * @param arr
+	 *            is an array to be swapped
+	 * @param i
+	 *            is index of first element
+	 * @param j
+	 *            is index of second element
+	 */
 	private static void swap(int[] arr, int i, int j) {
 		int temp = arr[i];
 		arr[i] = arr[j];