// Search an element in sorted and rotated
// array using single pass of Binary Search
#include <bits/stdc++.h>
using namespace std;
// Returns index of key in arr[l..h] if
// key is present, otherwise returns -1
int search(int arr[], int l, int h, int key)
{
if (l > h)
return -1;
int mid = (l + h) / 2;
if (arr[mid] == key)
return mid;
/* If arr[l...mid] is sorted */
if (arr[l] <= arr[mid]) {
/* As this subarray is sorted, we can quickly
check if key lies in half or other half */
if (key >= arr[l] && key <= arr[mid])
return search(arr, l, mid - 1, key);
/*If key not lies in first half subarray,
Divide other half into two subarrays,
such that we can quickly check if key lies
in other half */
return search(arr, mid + 1, h, key);
}
/* If arr[l..mid] first subarray is not sorted, then
arr[mid... h] must be sorted subarray */
if (key >= arr[mid] && key <= arr[h])
return search(arr, mid + 1, h, key);
return search(arr, l, mid - 1, key);
}
// Driver program
int main()
{
int arr[] = { 4, 5, 6, 7, 8, 9, 1, 2, 3 };
int n = sizeof(arr) / sizeof(arr[0]);
int key = 3;
int i = search(arr, 0, n - 1, key);
if (i != -1)
cout << "Index: " << i << endl;
else
cout << "Key not found";
}
// This code is contributed by Aditya Kumar (adityakumar129)