The Book Depository interview questions

Codility questions: 1- given and integer (as a binary string), you have two kinds of operations: if number is odd then subtract 1, else divide by 2. determine the number of operations to reach 0 in O(n) complexity and O(1) space. the tricky part here is you're not allowed to convert number to decimal format, not to violate the O(1) space constraint. 2- calculate reverse polish notation. Onsite interview: ============== Technical questions: 1- Given array of positive integers, design an algorithm to print the longest sequence in it (just the count, no need to print the sequence itself). (order is not important). i.e. [3,1, 4, 7, 2, 30, 9, 8] -> output: 4 they are expecting O(n) 2- Design cards deck (classes and relations .... etc). 3- Design a parking system (very similar to the above question).