"Senior software engineers are the most experienced member of a software team and usually carry the most responsibility and authority of that team. Because of this, interviews will be designed to find candidates who have expert knowledge of the field and years of experience as a software engineer. Expect to be asked tough technical questions and to give examples of previous projects that you have worked on."
You are given a fixed number of 5 rupee, 10 rupee, 20 rupee and 50 rupee stamps. Now given an amount for sending a parcel, you should design an algorithm to come out with the minimum number of stamps that should be used for attaining that amount. For example, if the parcel costed 30 rupees, it could be attained using one 20 rupee stamp and one 10 rupee stamp OR using three 10 rupee stamps OR using one 20 rupee stamp and two 5 rupee stamps OR using one 10 rupee stamp and four 5 rupee stamps OR using two 10 rupee stamps and two 5 rupee stamps. However, the minimum number of stamps is the case of one 20 rupee stamp and one 10 rupee stamp where only two stamps are used. The case where no solution is possible should also be handled, for example, a parcel amount of exactly 33 rupees cannot be attained.
The solution is attained using dynamic programming. The basic idea is that the minimum number of stamps used for attaining an amount x, is 1+minimum of (minimum number of stamps for attaining x-5, minimum number of stamps for attaining x-10, minimum number of stamps for attaining x-20,minimum number of stamps for attaining x-50). You can try to solve this first by assuming that an unlimited number of 5 rupee, 10 rupee, 20 rupee and 50 rupee stamps are available. And then you can take into account that only a fixed number of these stamps are available.
And what is the time involved to get this done? I really liked the question.Simple to read but involves good amount of logic. I ve written down the algorithm but i believe i took more time than i initially thought i would take.
I understand what the interviewer is trying to test and I know how to solve it, but what about more realistic scenario where parcel postage cost would be beyond given values like 3 units of currency or 37 units of currency.