Merge pull request #466 from Jagannath8/binary_search

Binary search (Java) added

Author: smv1999

Searching Algorithms/Binary_search.java

@@ -0,0 +1,40 @@
+// Binary search is used to search a key element from multiple elements in an array.
+
+class BinarySearch{
+    public static void binarySearch(int arr[], int first, int last, int key){
+        int mid = (first+last)/2;
+        while (first <= last){
+            
+            if (arr[mid]<key){
+                first = mid+1;
+            }
+            
+            else if(arr[mid]==key){
+                System.out.println("Element found at index: "+ mid);
+                break;
+            }
+            
+            else{
+                last = mid-1;
+            }
+            
+            mid = (first+last)/2;
+        }
+            
+        if(first > last){
+            System.out.println("Element not found");
+        }
+    }
+        
+        
+    public static void main (String[] args) {
+        int arr[] = {10,20,30,40,50};
+        int key=40;
+        int last = arr.length-1;
+        binarySearch(arr, 0, last, key);
+    }
+    
+}
+
+// Time Complexity = O(logn)
+// Space Complexity = O(1)