Create brace-expansion-ii.py

Author: kamyu104

Python/brace-expansion-ii.py

@@ -0,0 +1,89 @@
+# Time:  O(p*l * log(p*l)), p is the production of all number of options
+#                         , l is the length of a word
+# Space: O(p*l)
+
+import itertools
+
+
+class Solution(object):
+    def braceExpansionII(self, expression):
+        """
+        :type expression: str
+        :rtype: List[str]
+        """
+        def form_words(options):
+            words = map("".join, itertools.product(*options))
+            words.sort()
+            return words
+
+        def generate_option(expr, i):
+            option_set = set()
+            while i[0] != len(expr) and expr[i[0]] != "}":
+                i[0] += 1  # { or ,
+                for option in generate_words(expr, i):
+                    option_set.add(option)
+            i[0] += 1  # }
+            option = list(option_set)
+            option.sort()
+            return option
+
+        def generate_words(expr, i):
+            options = []
+            while i[0] != len(expr) and expr[i[0]] not in ",}":
+                tmp = []
+                if expr[i[0]] not in "{,}":
+                    tmp.append(expr[i[0]])
+                    i[0] += 1  # a-z
+                elif expr[i[0]] == "{":
+                    tmp = generate_option(expr, i)
+                options.append(tmp)
+            return form_words(options)
+
+        return generate_words(expression, [0])
+
+
+class Solution2(object):
+    def braceExpansionII(self, expression):
+        """
+        :type expression: str
+        :rtype: List[str]
+        """
+        def form_words(options):
+            words = []
+            total = 1
+            for opt in options:
+                total *= len(opt)
+            for i in xrange(total):
+                tmp = []
+                for opt in reversed(options):
+                    i, c = divmod(i, len(opt))
+                    tmp.append(opt[c])
+                tmp.reverse()
+                words.append("".join(tmp))
+            words.sort()
+            return words
+
+        def generate_option(expr, i):
+            option_set = set()
+            while i[0] != len(expr) and expr[i[0]] != "}":
+                i[0] += 1  # { or ,
+                for option in generate_words(expr, i):
+                    option_set.add(option)
+            i[0] += 1  # }
+            option = list(option_set)
+            option.sort()
+            return option
+
+        def generate_words(expr, i):
+            options = []
+            while i[0] != len(expr) and expr[i[0]] not in ",}":
+                tmp = []
+                if expr[i[0]] not in "{,}":
+                    tmp.append(expr[i[0]])
+                    i[0] += 1  # a-z
+                elif expr[i[0]] == "{":
+                    tmp = generate_option(expr, i)
+                options.append(tmp)
+            return form_words(options)
+
+        return generate_words(expression, [0])