int search(int* arr, int n, int key) {
int si = 0;
 int ei = n-1;
//     core concept : if array is rotated and we visited any index then one part
// of array is going to be sorted 
    while(si <= ei){
       int mid = (si + ei)/2;
        
        if(arr[mid] == key){
            return mid;
        }
        if(arr[mid]  >= arr[si]){ 
//             if mid == si this means left part has one element and that is sorted
//           left  array is sorted
            if(key < arr[mid] && key >= arr[si]){
                ei = mid - 1;
                continue;
            }else{
                si = mid + 1;
            }
        }
        if(arr[mid]  <= arr[ei]){
//             here arr[mid] can be equal to arr[ei] if there is only one 
//             element in whole array
//             righty array is sorted
//             
            if(key <= arr[ei]  && key > arr[mid]){
                si = mid + 1;
                
            }else{
                ei = mid - 1;
            }
            
        }
    }
   return -1;
}