CareerCup

public static int binarySearch(int[] sorted, int first, int upto, int key) {
    
    while (first < upto) {
        int mid = (first + upto) / 2;  // Compute mid point.
        if (key < sorted[mid]) {
            upto = mid;     // repeat search in bottom half.
        } else if (key > sorted[mid]) {
            first = mid + 1;  // Repeat search in top half.
        } else {
            return mid;     // Found it. return position
        }
    }
    return -(first + 1);    // Failed to find key
}

public static int search(int[] arr, int target) {
    return search(arr, target, 0, arr.length - 1);
  }
  
  private static int search(int[] arr, int target, int start, int end) {
    if (start > end) return -1;
    int mid = (start + end) / 2;
    if (arr[mid] == target) return mid;
    else if (arr[mid] > target) 
      return search(arr, target, start, mid - 1);
    else 
      return search(arr, target, mid + 1, end);
  }