REC_CMPL1

Asked in:
Goldman Sachs
Amazon

What is the worst case time complexity of the following code :

/* 
 * V is sorted 
 * V.size() = N
 * The function is initially called as searchNumOccurrence(V, k, 0, N-1)
 */
int searchNumOccurrence(vector<int> &V, int k, int start, int end) {
    if (start > end) return 0;
    int mid = (start + end) / 2;
    if (V[mid] < k) return searchNumOccurrence(V, k, mid + 1, end);
    if (V[mid] > k) return searchNumOccurrence(V, k, start, mid - 1);
    return searchNumOccurrence(V, k, start, mid - 1) + 1 + searchNumOccurrence(V, k, mid + 1, end);
}

NOTE : This question involves recursion which will be explained later in topic Backtracking. So, if you are not able to approach this question now, you can give it a try later.