Starts working on problem 49

e_47.py

@@ -20,9 +20,19 @@ Find the first four consecutive integers to have four distinct primes factors. W
 '''
 import pickle
 
+# list of primes up to one million.
+plist = pickle.load(open("primes_list.dup", "rb"))
+
+
+def is_prime(val):
+    """
+    Returns True if the number is prime
+    """
+    return (val in plist)
+
 def consecutive_primes(num):
     """
-    Returns the first of the firs num consecutive primes.
+    Returns the first of the first num consecutive primes.
     """
 
 

e_49.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+'''
+Created on 10 feb. 2012
+
+@author: Julien Lengrand-Lambert
+
+DESCRIPTION: Solves problem 49 of Project Euler
+The arithmetic sequence, 1487, 4817, 8147, in which each of the terms increases by 3330, is unusual in two ways:
+(i) each of the three terms are prime, and, (ii) each of the 4-digit numbers are permutations of one another.
+
+There are no arithmetic sequences made up of three 1-, 2-, or 3-digit primes, exhibiting this property,
+but there is one other 4-digit increasing sequence.
+
+What 12-digit number do you form by concatenating the three terms in this sequence?
+'''
+import pickle
+
+# list of primes up to one million.
+plist = pickle.load(open("primes_list.dup", "rb"))
+
+def fourLengthPrime():
+    """
+    Returns the list of all prime numbers of length 4
+    """
+    return(val for val in plist if len(str(val)) == 4)
+
+def isPrime(val):
+    """
+    Returns True if the number is prime
+    """
+    return (val in plist)
+
+def all_permutations(seq):
+    """permutate a sequence and return a list of the permutations"""
+    if not seq:
+        return [seq]  # is an empty sequence
+    else:
+        temp = []
+        for k in range(len(seq)):
+            part = seq[:k] + seq[k+1:]
+            for m in all_permutations(part):
+                temp.append(seq[k:k+1] + m)
+        return temp
+
+def getPrimesPermutations(primes, length):
+    """
+    Returns all the lists of primes that are permutations from one another,
+    and of size at least 3.
+    """
+    if True:
+    #for prime in primes :
+        prime = primes.next()
+        perms = [int(val) for val in all_permutations(str(prime))]
+        print perms
+
+def findPrimePerms(prime):
+    """
+    Returns all the list of primes that are permutations from prime
+    """
+    perms = [int(val) for val in all_permutations(str(prime)) if (isPrime(int(val)) and len(str(int(val))) == 4)]
+    res = list(set(perms)) # rermoves duplicates
+    if len(res) > 2:
+        return res
+
+if __name__ == '__main__':
+    primes = fourLengthPrime()
+    print findPrimePerms(primes.next())
+    print findPrimePerms(primes.next())
+    print findPrimePerms(primes.next())
+    print findPrimePerms(primes.next())
+    #print "Answer : %d " % (last_ten())