Technical Interview

Tips, questions, answers and puzzles at

Saturday, October 15, 2011

Classify the Hashing Functions based on the various methods by which the key value is found

Friday, September 30, 2011

Common multiple

Q: Given two numbers m and n, write a method to return the first number r that is
divisible by both (e.g., the least common multiple).

The Approach:
What does it mean for r to be divisible by m and n? It means that all the primes in m must go into r, and all primes in n must be in r. What if m and n have primes in common?

For example, if m is divisible by 3^5 and n is divisible by 3^7, what does this mean about r? It means r must be divisible by 3^7.

The Rule: For each prime p such that p^a \ m (e.g., m is divisible by p^a) and p^b \ n, r must be divisible by p^max(a, b)

The Algorithm:
Define q to be 1.
for each prime number p less than m and n:
find the largest a and b such that p^a \ m and p^b \ n
let q = q * p^max(a, b)
return q