Modernize Python 2 code to get ready for Python 3

Project Euler/Problem 01/sol1.py

@@ -4,9 +4,14 @@ If we list all the natural numbers below 10 that are multiples of 3 or 5,
 we get 3,5,6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 '''
+from __future__ import print_function
+try:
+    raw_input          # Python 2
+except NameError:
+    raw_input = input  # Python 3
 n = int(raw_input().strip())
-sum=0;
+sum=0
 for a in range(3,n):
     if(a%3==0 or a%5==0):
         sum+=a
-print sum;
+print(sum)

Project Euler/Problem 01/sol2.py

@@ -4,6 +4,11 @@ If we list all the natural numbers below 10 that are multiples of 3 or 5,
 we get 3,5,6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 '''
+from __future__ import print_function
+try:
+    raw_input          # Python 2
+except NameError:
+    raw_input = input  # Python 3
 n = int(raw_input().strip())
 sum = 0
 terms = (n-1)/3
@@ -12,4 +17,4 @@ terms = (n-1)/5
 sum+= ((terms)*(10+(terms-1)*5))/2
 terms = (n-1)/15
 sum-= ((terms)*(30+(terms-1)*15))/2
-print sum
+print(sum)

Project Euler/Problem 01/sol3.py

@@ -7,6 +7,11 @@ Find the sum of all the multiples of 3 or 5 below N.
 '''
 This solution is based on the pattern that the successive numbers in the series follow: 0+3,+2,+1,+3,+1,+2,+3.
 '''
+from __future__ import print_function
+try:
+    raw_input          # Python 2
+except NameError:
+    raw_input = input  # Python 3
 n = int(raw_input().strip())
 sum=0;
 num=0;
@@ -39,4 +44,4 @@ while(1):
     if(num>=n):
         break
     sum+=num
-print sum;
+print(sum);

Project Euler/Problem 02/sol1.py

@@ -6,6 +6,12 @@ the first 10 terms will be:
 By considering the terms in the Fibonacci sequence whose values do not exceed n, find the sum of the even-valued terms.
 e.g. for n=10, we have {2,8}, sum is 10.
 '''
+from __future__ import print_function
+
+try:
+    raw_input          # Python 2
+except NameError:
+    raw_input = input  # Python 3
 
 n = int(raw_input().strip())
 i=1; j=2; sum=0
@@ -15,4 +21,4 @@ while(j<=n):
     temp=i
     i=j
     j=temp+i
-print sum
+print(sum)

Project Euler/Problem 03/sol1.py

@@ -3,6 +3,7 @@ Problem:
 The prime factors of 13195 are 5,7,13 and 29. What is the largest prime factor of a given number N?
 e.g. for 10, largest prime factor = 5. For 17, largest prime factor = 17.
 '''
+from __future__ import print_function
 
 import math
 
@@ -20,12 +21,12 @@ def isprime(no):
 max=0
 n=int(input())
 if(isprime(n)):
-    print n
+    print(n)
 else:
     while (n%2==0):
         n=n/2
     if(isprime(n)):
-        print n
+        print(n)
     else:
         n1 = int(math.sqrt(n))+1
         for i in range(3,n1,2):
@@ -35,4 +36,4 @@ else:
                     break
                 elif(isprime(i)):
                     max=i
-        print max
+        print(max)

Project Euler/Problem 03/sol2.py

@@ -3,6 +3,7 @@ Problem:
 The prime factors of 13195 are 5,7,13 and 29. What is the largest prime factor of a given number N?
 e.g. for 10, largest prime factor = 5. For 17, largest prime factor = 17.
 '''
+from __future__ import print_function
 n=int(input())
 prime=1
 i=2
@@ -13,4 +14,4 @@ while(i*i<=n):
     i+=1
 if(n>1):
     prime=n
-print prime
+print(prime)

Project Euler/Problem 04/sol1.py

@@ -3,6 +3,7 @@ Problem:
 A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 x 99.
 Find the largest palindrome made from the product of two 3-digit numbers which is less than N.
 '''
+from __future__ import print_function
 n=int(input())
 for i in range(n-1,10000,-1):
     temp=str(i)
@@ -10,6 +11,6 @@ for i in range(n-1,10000,-1):
         j=999
         while(j!=99):
             if((i%j==0) and (len(str(i/j))==3)):
-                print i
+                print(i)
                 exit(0)
             j-=1

Project Euler/Problem 04/sol2.py

@@ -3,6 +3,7 @@ Problem:
 A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 x 99.
 Find the largest palindrome made from the product of two 3-digit numbers which is less than N.
 '''
+from __future__ import print_function
 arr = []
 for i in range(999,100,-1):
     for j in range(999,100,-1):
@@ -14,5 +15,5 @@ arr.sort()
 n=int(input())
 for i in arr[::-1]:
     if(i<n):
-        print i
+        print(i)
         exit(0)

Project Euler/Problem 05/sol1.py

@@ -3,6 +3,7 @@ Problem:
 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
 What is the smallest positive number that is evenly divisible(divisible with no remainder) by all of the numbers from 1 to N?
 '''
+from __future__ import print_function
 
 n = int(input())
 i = 0
@@ -16,5 +17,5 @@ while 1:
     if(nfound==0):
         if(i==0):
             i=1
-        print i
+        print(i)
         break

Project Euler/Problem 06/sol1.py

@@ -8,6 +8,7 @@ The square of the sum of the first ten natural numbers is,
 Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.
 Find the difference between the sum of the squares of the first N natural numbers and the square of the sum.
 '''
+from __future__ import print_function
 
 suma = 0
 sumb = 0
@@ -16,4 +17,4 @@ for i in range(1,n+1):
     suma += i**2
     sumb += i
 sum = sumb**2 - suma
-print sum
+print(sum)

Project Euler/Problem 06/sol2.py

@@ -8,8 +8,9 @@ The square of the sum of the first ten natural numbers is,
 Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.
 Find the difference between the sum of the squares of the first N natural numbers and the square of the sum.
 '''
+from __future__ import print_function
 n = int(input())
 suma = n*(n+1)/2
 suma **= 2
 sumb = n*(n+1)*(2*n+1)/6
-print suma-sumb
+print(suma-sumb)

Project Euler/Problem 07/sol1.py

@@ -3,6 +3,7 @@ By listing the first six prime numbers:
 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.
 What is the Nth prime number?
 '''
+from __future__ import print_function
 from math import sqrt
 def isprime(n):
     if (n==2):
@@ -26,4 +27,4 @@ while(i!=n):
     j+=2
     if(isprime(j)):
         i+=1
-print j
+print(j)

Project Euler/Problem 13/sol1.py

@@ -2,6 +2,7 @@
 Problem Statement:
 Work out the first ten digits of the sum of the N 50-digit numbers.
 '''
+from __future__ import print_function
 
 n = int(input().strip())
 

Project Euler/Problem 14/sol1.py

@@ -1,3 +1,4 @@
+from __future__ import print_function
 largest_number = 0
 pre_counter = 0
 
@@ -17,4 +18,4 @@ for input1 in range(750000,1000000):
         largest_number = input1
         pre_counter = counter
 
-print('Largest Number:',largest_number,'->',pre_counter,'digits')
+print(('Largest Number:',largest_number,'->',pre_counter,'digits'))

Project Euler/Problem 9/sol1.py

@@ -1,3 +1,4 @@
+from __future__ import print_function
 # Program to find the product of a,b,c which are Pythagorean Triplet that satisfice the following:
 # 1. a < b < c
 # 2. a**2 + b**2 = c**2
@@ -10,5 +11,5 @@ for a in range(300):
             if(a < b < c):
                 if((a**2) + (b**2) == (c**2)):
                     if((a+b+c) == 1000):
-                        print("Product of",a,"*",b,"*",c,"=",(a*b*c))
+                        print(("Product of",a,"*",b,"*",c,"=",(a*b*c)))
                         break