Sunday, September 30, 2012

A great machine learning book

Many times people are asking  what is the best book to start studying machine learning. Among other books, I'd like to suggest: Machine Learning, An algorithmic Perspective, which has a good mix of topics covered and where every algorithm is implemented in python

Saturday, September 29, 2012

Exit a labyrinth

given a matrix of 0/1, where the 1s represent the walls of a labyrinth, find the exit

Friday, September 28, 2012

My view on Facebook Gift

Gift could be a changing moment for Facebook. In my view, this is a service with a great user experience and it also has opportunities for increasing FB's revenues. In my view, Facebook can become a cash-cow but they need to add services for allowing money transfer or gift transfers ( see my posting on this topic of about 1 year ago " )

Tuesday, September 25, 2012

Given a tree, return an array A

where A[i] is the head of a linked list containing all the elements at level i.

Friday, September 21, 2012


Explain the intuition behind SVM and optionally try to figure out the math

Tuesday, September 18, 2012

Select friends from your social network

You need to select the maximum number of friends in your network and invite them to a party. The requirement is that each friend knows a minimum of 5 friends and she does not know at least 5 other friends.

Thursday, September 13, 2012

Unsorted array

Given an unsorted array, how to divide them into two equal arrays whose difference of sum is minimum

Wednesday, September 12, 2012

Sort a large set of std::vector

Sort a large set of std::vector, larger than the size of RAM

Tuesday, September 11, 2012

Array rotation

Given an array, rotate the elements of an array within O(n) time and with 0(1) space

Monday, September 10, 2012

A frog jumping

A frog can jump a river of n meters and at each step she can jump either x-1 or x or x+1 meter if she jumped x meter at the previous step. She can jump just if the starting place and the ending place has a stone. The available stones are maintained in an array S[i] given as input. The first just is just 1 meter. Can you compute whether or not the frog will arrive at the destination?

Sunday, September 9, 2012

implement a first fit strategy

You have a m set of boxes of different sizes and a set of n envelopes. Find a strategy to fit the box in the envelopes

Thursday, September 6, 2012

an url can contain words

an url can contain words. For instance Device an algorithm for extracting all the words from an url

Wednesday, September 5, 2012

Longest subsequence

Given an array A of integers such that #A = n, find the longest sequence such that i_j < i_{j+1} and A[i_j] <= A[i_{j+1}] for any j \in [1, k-1]

Tuesday, September 4, 2012

Max sum in an array

Given an array of integers A find a, b such that \sum_{i=a}^b A[i] is maximized

Sunday, September 2, 2012

Search engines and monetization

Search engines are making money selling ads. Can you envision any different strategy?

Saturday, September 1, 2012

inverted lists

Given a very large set of document, you can define the following relation d_i ->; w_a, w_b, w_c, ...... meaning that the document d_i contains the word w_a, w_b, w_c, and so on and so forth

Suppose you want to invert the relation and build lists such as

w_a -> d_i, d_j, d_k ...

meaning that the word w_a is contained in documents  d_i, d_j, d_k ...

how would you proceeed?