backtracking

Author: idf

411 Minimum Unique Word Abbreviation.py

@@ -0,0 +1,73 @@
+"""
+Premium Question
+"""
+__author__ = 'Daniel'
+
+
+class Solution(object):
+    def minAbbreviation(self, target, dictionary):
+        """
+        :type target: str
+        :type dictionary: List[str]
+        :rtype: str
+        """
+        ret = target
+        for abbr in self.dfs(target):
+            if self.validate(dictionary, abbr) and len(ret) > len(abbr):
+                ret = abbr
+
+        return ret
+
+    def dfs(self, word):
+        """
+        backtracking, pivoting letter
+        :type word: str
+        :rtype: List[str]
+        """
+        if not word:
+            return [""]
+
+        ret = []
+        for l in xrange(len(word)+1):
+            left_num = str(l) if l else ""
+            for right in self.dfs(word[l+1:]):
+                cur = left_num+word[l:l+1]+right
+                ret.append(cur)
+
+        return ret
+
+    def validate(self, dictionary, abbr):
+        for w in dictionary:
+            if self.validWordAbbreviation(w, abbr):
+                return False
+
+        return True
+
+    def validWordAbbreviation(self, word, abbr):
+        """
+        pointers
+        :type word: str
+        :type abbr: str
+        :rtype: bool
+        """
+        w = 0
+        a = 0
+        while w < len(word) and a < len(abbr):
+            if abbr[a].isdigit() and abbr[a] != '0':
+                e = a
+                while e < len(abbr) and abbr[e].isdigit(): e += 1
+                num = int(abbr[a:e])
+                a = e
+                w += num
+            else:
+                if word[w] != abbr[a]:
+                    return False
+
+                w += 1
+                a += 1
+
+        return w == len(word) and a == len(abbr)
+
+
+if __name__ == "__main__":
+    print Solution().minAbbreviation("apple", ["blade"])