Adding permutations

Author: elmar-hinz

challenges/challenge.py

@@ -3,12 +3,10 @@
 This module holds the base class of all challenges.
 """
 
-import math
 import re
-
+import math
 import types
 
-
 class Challenge:
     """Base class of all challenges
 
@@ -251,6 +249,30 @@ def line_to_edge(self, nr):
         match = re.compile(self.edge_pattern).match(self.line(nr))
         return self._to_edge(match)
 
+    def line_to_permutation(self, nr, terminals = False):
+        """Convert one line to a permutation
+
+        optionally surrounded by terminals
+
+        Example: (+1 -3, -2)
+        Result: [1, -3, 2]
+        If terminals is True: [0, 1, -3, 2, 4]
+
+        The number of the line is selected by line_nr.
+        Input may be surrounded by a pair of round parenthesis.
+        The split behaviour can be adjusted by changing self.edge_pattern.
+        """
+        line = self.line(nr)
+        match = re.compile('^\((.*)\)$').match(line)
+        if match:
+            digits = match.group(1)
+        else:
+            digits = line
+        perm =  [int(d) for d in re.compile(self.split_pattern).split(digits)]
+        if terminals:
+            perm = [0] + perm + [len(perm) + 1]
+        return perm
+
     def edges(self, start=0, stop=None):
         """Generator to read edges from lines.
 
@@ -355,3 +377,11 @@ def format_path(self, integers, backwards=False):
         else:
             joint = '->'
         return self.format_list_of_integers(integers, joint)
+
+    def format_permutations(self, permutations):
+        output = ''
+        for perm in permutations:
+            output += '('
+            output += ' '.join(('+' if i > 0 else '') + str(i) for i in perm)
+            output += ')' + self.br
+        return output[:-1]

tests/test_challenge.py

@@ -71,6 +71,24 @@ def test_line(self):
         self.challenge.lines = ['one', 'two', 'three']
         self.assertEqual(self.challenge.line(1), 'two')
 
+    def test_line_to_permuation(self):
+        """Show a line can be retrieved as permutation."""
+        self.challenge.lines = ['one', '+1 -2']
+        result = self.challenge.line_to_permutation(1)
+        self.assertEqual(result, [1, -2])
+
+    def test_line_to_permuation_with_parenthesis(self):
+        """Show a line can be retrieved as permutation."""
+        self.challenge.lines = ['one', '(+1 -2)']
+        result = self.challenge.line_to_permutation(1)
+        self.assertEqual(result, [1, -2])
+
+    def test_line_to_permuation_surrounded_with_terminals(self):
+        """Show a line can be retrieved as permutation."""
+        self.challenge.lines = ['one', '+1 -2']
+        result = self.challenge.line_to_permutation(1)
+        self.assertEqual(result, [1, -2])
+
     def test_line_to_integers(self):
         """Show a line can be retrieved as integers."""
         self.challenge.lines = ['one', '1, 2, 3']
@@ -260,3 +278,10 @@ def test_format_path(self):
         self.assertEqual(result, '11->22->33')
         result = self.challenge.format_path([11, 22, 33], backwards=True)
         self.assertEqual(result, '11<-22<-33')
+
+    def test_format_permuations(self):
+        """Show a list of permuations can be formatted."""
+        list = [[1, -2], [-3, 4]]
+        actual = self.challenge.format_permutations(list)
+        expect = '(+1 -2)\n(-3 +4)'
+        self.assertEqual(expect, actual)