"Tower of Hanoi" is a famous task. It has a simple recursive solution.
Today I'll show how to find a loop in linked list with a linear time complexity.
Some interview question can be solved by dynamic programming.
One of such is a coin problem - express an amount of money with the minimal coin number.
Another interesting task for interview is "Longest substring without repeating characters".
Usual interview task is: Print all possible n pairs of balanced parentheses.