selection sort : done

Author: Ram swaroop

src/me/ramswaroop/arrays/SelectionSort.java

@@ -0,0 +1,59 @@
+package me.ramswaroop.arrays;
+
+import java.util.Arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 8/22/15
+ * @time: 12:28 PM
+ */
+public class SelectionSort {
+
+    /**
+     * Selection Sort.
+     * 
+     * Explanation: 
+     * This is one of the simplest algorithm where each time the smallest/largest
+     * element is chosen and placed at the appropriate position and then again the
+     * logic is applied on rest of the elements till the entire array is sorted.
+     * 
+     * Time complexity: O(n) for all cases.
+     * 
+     * NOTE: Advantage of this sort is that it requires minimum number of memory writes
+     * like Cycle sort. 
+     * 
+     * 
+     * @param a
+     */
+    public static void selectionSort(int[] a) {
+        int minIndex;
+
+        for (int i = 0; i < a.length - 1; i++) {
+            minIndex = i;
+            for (int j = i + 1; j < a.length; j++) {
+                if (a[j] < a[minIndex]) {
+                    minIndex = j;
+                }
+            }
+            swap(a, i, minIndex);
+        }
+    }
+
+    private static void swap(int[] a, int index1, int index2) {
+        int temp = a[index1];
+        a[index1] = a[index2];
+        a[index2] = temp;
+    }
+
+    public static void main(String a[]) {
+        int[] ar = new int[]{3, 2, 1, 5, 6, 9, 7, 10};
+        selectionSort(ar);
+        System.out.println(Arrays.toString(ar));
+
+        ar = new int[]{3, 2, 1, 5, 5, 6, 9, 7, 6, 10};
+        selectionSort(ar);
+        System.out.println(Arrays.toString(ar));
+    }
+}