Merge pull request #408 from thegabriele97/master

added iterative binary search algorithm

Author: Christian Bender

Searches/IterativeBinarySearch.java

@@ -0,0 +1,59 @@
+
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * 
+ * @author Gabriele La Greca : https://github.com/thegabriele97
+ * 
+ */
+
+public final class IterativeBinarySearch {
+
+    /**
+     * This method implements an iterative version of binary search algorithm
+     * 
+     * @param array a sorted array
+     * @param key the key to search in array
+     * 
+     * @return the index of key in the array or -1 if not found
+     */
+    public static <T extends Comparable<T>> int binarySearch(T[] array, T key) {
+        int l, r, k, cmp;
+
+        l = 0;
+        r = array.length - 1;
+
+        while (l <= r) {
+            k = (l + r) / 2;
+            cmp = key.compareTo(array[k]);
+
+            if (cmp == 0) {
+                return k;
+            } else if (cmp < 0) {
+                r = --k;
+            } else if (cmp > 0) {
+                l = ++k;
+            }
+        }
+
+        return -1;
+    }
+
+    //Only a main method for test purpose
+    public static void main(String[] args) {
+        Random rand = new Random();
+        int base = rand.nextInt(1000);
+
+        Integer[] array = new Integer[65535];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = base + (i + 1);
+        }
+
+        //Arrays.sort(array); //if needed
+        Integer key = base + rand.nextInt(array.length * 2); //can generate keys that aren't in array
+
+        System.out.println(binarySearch(array, key));
+        System.out.println(Arrays.binarySearch(array, key));
+    }
+}