Explain scheduling in OS

Out of my skillset, which aspect did I consider as my primary skill and they should consider a primary reason why they hire me.

Why do you want to change your job?

You're given a binary tree and pointers to two nodes in the tree. Describe the fastest algorithm you can come up with to determine the closest common ancestor.

You're writing an application that receives a stream of individual items of data. The stream may be very long or very short, but you have no way of knowing how long it is (i.e. there's no trick to figuring out the size of the stream of data). How would you go about choosing m items such that any subset of m items was equally likely? (Not an even distribution of values, but just that any m items are equally likely to be chosen). So for example, m=1000, and the number of items in the stream, n, may be 1000, or 10000, or 100000000, or much much larger; there is no way to know how many.

Why are manhole covers round?

What is Google's next million dollar ida?

What could be improved on AdWords or Analytics?

Given an integer, write a c++ code that would count the number of bit positions that are set (1's)? What is the time complexity of your algorithm?

Assume you were asked to improve it such that you would get the results instantaneously. What would you do?

Write ArrayList in Java.

How would you implement a stack with the additional operation of getMin?

Given a string and a list of character mappings of the form (a=>j,k), (d=>r), (t=>r,q,e,y), print out all the possible variants by applying the mapping to the original string.
example:
string="foo", mappings = "o=>1,2", "k=>d,l,w"
output:
foo
fo1
fo2
f1o
f11
f12
f2o
f21
f22