Simplify code by dropping support for legacy Python (#1143)

* Simplify code by dropping support for legacy Python

* sort() --> sorted()

dynamic_programming/integer_partition.py

@@ -1,27 +1,15 @@
-from __future__ import print_function
-
-try:
-	xrange		#Python 2
-except NameError:
-	xrange = range	#Python 3
-
-try:
-	raw_input		#Python 2
-except NameError:
-	raw_input = input	#Python 3
-
 '''
 The number of partitions of a number n into at least k parts equals the number of partitions into exactly k parts
 plus the number of partitions into at least k-1 parts. Subtracting 1 from each part of a partition of n into k parts
 gives a partition of n-k into k parts. These two facts together are used for this algorithm.
 '''
 def partition(m):
-	memo = [[0 for _ in xrange(m)] for _ in xrange(m+1)]
-	for i in xrange(m+1):
+	memo = [[0 for _ in range(m)] for _ in range(m+1)]
+	for i in range(m+1):
 		memo[i][0] = 1
 
-	for n in xrange(m+1):
-		for k in xrange(1, m):
+	for n in range(m+1):
+		for k in range(1, m):
 			memo[n][k] += memo[n][k-1]
 			if n-k > 0:
 				memo[n][k] += memo[n-k-1][k]
@@ -33,7 +21,7 @@ if __name__ == '__main__':
 
 	if len(sys.argv) == 1:
 		try:
-			n = int(raw_input('Enter a number: '))
+			n = int(input('Enter a number: ').strip())
 			print(partition(n))
 		except ValueError:
 			print('Please enter a number.')