Binary Search algorithm (eugenp#2448)

techPackets · maibin · commit da3273af6ebe · 2017-08-15T22:56:42.000-07:00
diff --git a/algorithms/src/main/java/com/baeldung/algorithms/BinarySearch.java b/algorithms/src/main/java/com/baeldung/algorithms/BinarySearch.java
@@ -0,0 +1,26 @@
+public class BinarySearch {
+
+    public int runBinarySearch() {
+        int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+        int key = 6;
+
+        int low = 0;
+        int high = sortedArray.length - 1;
+        int index = Integer.MAX_VALUE;
+
+        while (low <= high) {
+
+            int mid = (low + high) / 2;
+
+            if (sortedArray[mid] < key) {
+                low = mid + 1;
+            } else if (sortedArray[mid] > key) {
+                high = mid - 1;
+            } else if (sortedArray[mid] == key) {
+                index = mid;
+                break;
+            }
+        }
+        return index;
+    }
+}
diff --git a/algorithms/src/test/java/algorithms/BinarySearchTest.java b/algorithms/src/test/java/algorithms/BinarySearchTest.java
@@ -0,0 +1,14 @@
+import org.junit.Assert;
+import org.junit.Test;
+
+
+public class BinarySearchTest {
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        int expectedIndexForSearchKey = 7;
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearch());
+    }
+
+}
