Microsoft Software Engineer(Internship) interview questions

What is the minimal number of coins you will need in order to reach a target. They give you the currency ex. [1,2,3,4,5,6] and the target ex. 28. you will need to return the number of minimal coins in order to reach the target.

Q: Given a string, find the longest sub-string of distinct characters. Give it's time and space analysis. Q: Given a number, determine if it contains no more than one appearance of any number in a given set. Q: Given a simple clock and the current time, how would you find the angle between the hour and minute hand? Q: Construct a data structure in order to implement a tree with an arbitrary number of children. Implement functions to perform delete, insert, and lookup of nodes. Q: Given a string, compress it so that aaabbbccc becomes 3a3b3c etc.