Random commentary about Machine Learning, BigData, Spark, Deep Learning, C++, STL, Boost, Perl, Python, Algorithms, Problem Solving and Web Search
Saturday, June 30, 2012
Min and Max
Find the min and max in an array. Now do it in less than 2n comparisons
Friday, June 29, 2012
Event store
Question: Design a component that implements the following functionality..
1) Record an Event (For the sake of simplicity, treat the Event as an integer code)
2) Return the number of Events recorded in the last one minute.
3) Return the number of Events recorded in the last one hour.
i.e implement the following interface
Thursday, June 28, 2012
Points closer to a point
You are given a list of points in the plane, write a program that outputs each point along with the three other points that are closest to it. These three points ordered by distance.
Wednesday, June 27, 2012
Last 60secs
Create a data structure which is supposed to log number of user requests per second. At any point of time your boss can ask you the number of hits for the last 60 seconds.
Tuesday, June 26, 2012
Monday, June 25, 2012
Reverse words
Given a file with billions of records data. The file is too large to in main memory, and you need to reverse each word in that file and then save the reversed words to another file.
Sunday, June 24, 2012
Creative d80 -- Bluetooth wireless music box
I recently bought a Creative d80 -- Bluetooth wireless music box and my impression is WOW!! It is very cheap just less than $40 and the quality of music is impressive. I can stream over Bluetooth from my iphone, ipad, android, winphone, and windows 7. I don't have a Mac but it seems as easy as the remaining ones. If you have win7 make sure that your Bluetooth device has a stack supporting a2dp or enhanced data rate.
Geek is about founding creative and inexpensive cool technologies.
Geek is about founding creative and inexpensive cool technologies.
Saturday, June 23, 2012
This Ph.D. thesis changed the world as we know. 100 years. A true hero, with solid principles
https://webspace.princeton.edu/users/jedwards/Turing%20Centennial%202012/Mudd%20Archive%20files/12285_AC100_Turing_1938.pdf
https://webspace.princeton.edu/users/jedwards/Turing%20Centennial%202012/Mudd%20Archive%20files/12285_AC100_Turing_1938.pdf
Friday, June 22, 2012
Thursday, June 21, 2012
Tuesday, June 19, 2012
Monday, June 18, 2012
maximal subsets
Given a set S, find all the maximal subsets whose sum <= k. For example, if S = {1, 2, 3, 4, 5} and k = 7
Output is: {1, 2, 3} {1, 2, 4} {1, 5} {2, 5} {3, 4}
Sunday, June 17, 2012
Lucky numbers are numbers whose prime factors are just 2, 3, 5.
Find the first k lucky numbers.
Saturday, June 16, 2012
Value of A and B
Given two sorted positive integer rrays A(n) and B(n). We define a set S = {(a,b) such that a in A and b in B}. Obviously there are n^2 elements in S. The value of such a pair is defined as Val(a,b) = a + b. Now we want to get the n pairs from S with largest values. The tricky part is that we need an O(n)
algorithm.
Friday, June 15, 2012
true and false
Given a function bool Zoo(int x) and its called for y times , how you will generate the true with probability x/y times .
Thursday, June 14, 2012
Wednesday, June 13, 2012
Eggdrops
Solve the classical Google's interview problem.
Dynamic programming
Dynamic programming
k: Number of floors
n: Number of Eggs
eggDrop(n, k): Minimum number of trails needed to find the critical floor in worst case.
1) If the egg breaks after dropping from xth floor, then we only need to check for floors lower than x with remaining eggs; so the problem reduces to x-1 floors and n-1 eggs
2) If the egg doesn’t break after dropping from the xth floor, then we only need to check for floors higher than x; so the problem reduces to k-x floors and n eggs.
eggDrop(n, k) = 1 + min{max(eggDrop(n - 1, x - 1), eggDrop(n, k - x)): x in {1, 2, ..., k}}
Tuesday, June 12, 2012
you have a fleet of trucks and each truck has an autonomy of 1000KMs
How many kms in total you can cover if all the trucks start from the same place?
You have 25 horses and you can make races of 5 of them in parallell
How many races to get the top 3 horses?
Monday, June 11, 2012
A feature request for Facebook
Sometime I just want to pin a thread and follow it without expressing an explicit like. Would it be possible to just follow a thread?
Sunday, June 10, 2012
Monetizing free login
Several different providers are offering universal login schema, including Microsoft, Linkedin and Facebook. Apparently, none is monetizing this phase while there are plenty of opportunities to be leveraged.
Let's analyse a simple scenario where Alice, a Spotify user, decides to login using her Facebook account. Facebook knows Alice's geo-location, Alice's profile, Alice's past postings and likes. So Facebook has a lot of information to be mined for serving ads while Spotify does not have the same information. In other words, Facebook can sell ads to Spotify's users. So this could be the "Adsense" program for Facebook.
So my question is why Facebook is not opening this ads platform?
Let's analyse a simple scenario where Alice, a Spotify user, decides to login using her Facebook account. Facebook knows Alice's geo-location, Alice's profile, Alice's past postings and likes. So Facebook has a lot of information to be mined for serving ads while Spotify does not have the same information. In other words, Facebook can sell ads to Spotify's users. So this could be the "Adsense" program for Facebook.
So my question is why Facebook is not opening this ads platform?
Saturday, June 9, 2012
Friday, June 8, 2012
Thursday, June 7, 2012
Phonebook
Data structure TO use to design a phonebook. What is time complexity for retrieving, adding, and deleting entries
Wednesday, June 6, 2012
Tuesday, June 5, 2012
Monday, June 4, 2012
Write a function that takes 2 arguments: a binary tree and an integer n, it should return the n-th element in the inorder traversal of the binary tree
int findNthElementByInorder(Node *node, int &n) { if (node == null) return -1; findNthElementByInorder(node->left, n); if (n == 0) return node-> value; else n--; findNthElementByInorder(node->right, n); }
N-th
Write a function that takes 2 arguments: a binary tree and an integer n, it should return the n-th element in the inorder traversal of the binary tree.
int findNthElementByInorder(Node *node, int &n) { if (node == null) return -1; findNthElementByInorder(node->left, n); if (n == 0) return node-> value; else n--; findNthElementByInorder(node->right, n); }
Sunday, June 3, 2012
Reverse a linked list
Node* reverseLL(Node* n) { Node* curr = n; Node* prev = null; while(curr !=null) { Node* temp = curr.next; curr.next = prev; prev = curr; curr = temp; } return prev; }
Saturday, June 2, 2012
Duch national problem
void threeWayPartition(int data[], int size, int low, int high) { int p = -1; int q = size; for (int i = 0; i < q;) { if (data[i] < low) { swap(data[i], data[++p]); ++i; } else if (data[i] >= high) { swap(data[i], data[--q]); } else { ++i; } }
Friday, June 1, 2012
Given array find 3 elements that sum up to 0
For each i = 1..length do left = 0, right = length While left < i and right > i do if values[left] + values[i] + values[right] == 0 # Got solution here if values[left] + values[i] + values[right] > 0 # means that right border should be moved right-- else # moving left border left++
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