Create Rotated_Binary_Search.java

src/test/java/com/thealgorithms/searches/Rotated_Binary_Search.java

@@ -0,0 +1,57 @@
+// This is returning the index of that element
+class Rotated_Binary_Search{
+  public static void main(String[] args) {
+
+        int[] arr = { 4, 5, 6, 7, 0, 1, 2 };
+        System.out.println(search(arr,5));
+    }
+
+    static int search(int[] nums, int target) {
+        int pivot = findPivot(nums);
+        if(pivot ==-1){
+            return Binarysearch(nums, target, 0, nums.length-1);
+        }
+        if(nums[pivot]==target){
+            return pivot;
+        }
+        if(target>=nums[0]){
+            return Binarysearch(nums, target, 0, pivot-1);
+        }
+        return Binarysearch(nums, target, pivot+1, nums.length-1);
+    }
+
+    static int Binarysearch(int[] arr, int target, int start, int end) {
+
+        while (start <= end) {
+            int mid = start + (end - start) / 2;
+            if (target < arr[mid]) {
+                end = mid - 1;
+            } else if (target > arr[mid]) {
+                start = mid + 1;
+            } else {
+                return mid;
+            }
+        }
+        return -1;
+    }
+
+    static int findPivot(int[] arr) {
+        int start = 0;
+        int end = arr.length - 1;
+        while (start <= end) {
+            int mid = start + (end - start) / 2;
+            if (mid < end && arr[mid] > arr[mid + 1]) {
+                return mid;
+            }
+            if (mid > start && arr[mid] < arr[mid - 1]) {
+                return mid - 1;
+            }
+            if (arr[mid] <= arr[start]) {
+                end = mid - 1;
+            } else {
+                start = mid + 1;
+            }
+        }
+        return -1;
+    }
+}