Saturday, December 29, 2007

Project Euler 39

After a long time , but here is another project euler problem that I worked on.

This one was quite fun.

The number 3797 has an interesting property. Being prime itself, it is possible to continuously remove digits from left to right, and remain prime at each stage: 3797, 797, 97, and 7. Similarly we can work from right to left: 3797, 379, 37, and 3.

Find the sum of the only eleven primes that are both truncatable from left to right and right to left.

NOTE: 2, 3, 5, and 7 are not considered to be truncatable primes.


Again its a brute force ( takes a while to get the last prime) ,

I use a generator I found online to get the list of primes and then check if it left and right truncatable.

import time
from itertools import ifilter, count

def isPrime(n):
if n == 1:
return False

i = n - 1
while i > 1:
rem = n % i
if rem == 0:
return False
i = i - 1
return True

def truncateLeft(num):

k = num

while k != 0:
k /= 10
if not isPrime(k):
return False
return True

def truncateRight(num):
k = num

while k != 0:
k %=(10**(len(str(k))-1))
if not isPrime(k):
return False
return True

def sieve():
g = count(2)
while True:
prime =
yield prime
g = ifilter(lambda x, prime=prime: x % prime,g)

candidates = []

t = time.time()

primes = sieve()
start =

while len(candidates) != 11:
if truncateLeft(start) and truncateRight(start) and start > 7:
print str(start) + " has been added"
start =

print sum(candidates)
print time.time() - t

Thursday, September 20, 2007

Sony Ericsson has some of the best designs for phones, just have a look at this one:-

Saturday, September 01, 2007

I dont even know what to post about anymore, but I will post more often ...... in other news last week I was in New Orleans for company training and now I am a SCRUM Master :)

Friday, August 03, 2007

Project Euler #39

This is my solution for Project Euler #39

its definitely brute force and im sure there is a better way to get the answer, but here we go

f p is the perimeter of a right angle triangle with integral length sides, {a,b,c}, there are exactly three solutions for p = 120.

{20,48,52}, {24,45,51}, {30,40,50}

For which value of p 1000, is the number of solutions maximised?

My Solution:-

import math, time

t = time.time()

maximum = {}

for a in xrange(1,500):
for b in xrange(1,500):
c = math.sqrt(pow(a,2)+pow(b,2))
p = a+b+c
if p == int(p) and p < 1000:
if maximum.has_key(p):
maximum[p] += 1
maximum[p] = 1

e = maximum.keys()
e.sort(cmp = lambda a,b: cmp(maximum[a],maximum[b]))
print e[-1]
print time.time()-t

Friday, July 13, 2007

Namespaces for PHP

I read this kinda late, but namespaces were definitely required in php and now they have been made official

Thursday, July 05, 2007

Project Euler

I am completely addicted to this site...its all about solving math problems using programming.

Here is the solution to one of the problems

How Many Lychrel Numbers are below 10,000 ?

my solution in python, which takes abt 39 seconds:-

def lychrel(x):
i = 0
while i < 50:
x += int(str(x)[::-1])
if str(x) == str(x)[::-1]:
return False
i += 1
return True

print len ([x for x in range(1,10000) if lychrel(x)])

Saturday, May 26, 2007

Microsoft Popfly

So today I got an invite for microsoft's popfly . Popfly seems to be msfts take on letting users create mashups, websites , communities etc without typing in a single line of code and is powered by silverlight. The key word here being "user" which means anyone can create a mashup without knowing how things work behind the scenes.

The site is in alpha, and there are definitely some issues that I have come across. But the UI is amazing, it works with firefox ( big plus ! ).

I will be messing around with this and see what mashups I can come up with. Please feel free to add me as a friend ( ) and I will post invites for users as soon as I get them :)

Sunday, May 06, 2007

Vice Funds

I read about vice funds a while back on From the site the fund invests in alcohol, tobacco, gaming, aerospace and defense stocks. It is an interesting concept because in many ways people are addicted to this stuff and they have had very nice yearly returns ( close to 14.3%/yr ) to back their idea.

Now for anyone who still reads this would you invest in it ? Abhi , I think I already know your answer :)
I need to start posting stuff here again ....

Saturday, February 24, 2007

Roman Numeral Converter

One more codegolf challenge:-

In this challenge, you will be given a number in roman numeral form and must print out its integer value.

( from codegolf)

My latest solution at 129 bytes:-

for j in raw_input():s+=r[j]-(0,l*2)[r[j]>l];l=r[j]
print s

Any other ideas ?


After manzo's comment, I searched a little and came up with this. Right now its at 119 bytes

for j in raw_input():s+=r[j]-(0,l*2)[r[j]>l];l=r[j]
print s

Saturday, January 06, 2007

Colors for Visual Studio

Having watched a lot of videos featuring textmate, I really liked the color scheme that was being used by a lot of the videos. After some searching I came across Scott Hanselmans blog where he suggests some colors that bring it quite close.

This is what my current setting looks like:-

Any ideas for the colors of the html tag names other than white ?