Create number-of-valid-words-for-each-puzzle.py

Author: kamyu104

Python/number-of-valid-words-for-each-puzzle.py

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+# Time:  O(n*l + m*L), m is the number of puzzles, L is the length of puzzles
+#                    , n is the number of words, l is the max length of words
+# Space: O(L!)
+
+class Solution(object):
+    def findNumOfValidWords(self, words, puzzles):
+        """
+        :type words: List[str]
+        :type puzzles: List[str]
+        :rtype: List[int]
+        """
+        L = 7
+        def search(node, puzzle, start, first, met_first):
+            result = 0
+            if "_end" in node and met_first:
+                result += node["_end"];
+            for i in xrange(start, len(puzzle)):
+                if puzzle[i] not in node:
+                    continue
+                result += search(node[puzzle[i]], puzzle, i+1,
+                                 first, met_first or (puzzle[i] == first))
+            return result
+
+        _trie = lambda: collections.defaultdict(_trie)
+        trie = _trie()
+        for word in words:
+            count = set(word)
+            if len(count) > L:
+                continue
+            word = sorted(count)
+            end = reduce(dict.__getitem__, word, trie)
+            end["_end"] = end["_end"]+1 if "_end" in end else 1
+        result = []
+        for puzzle in puzzles:
+            first = puzzle[0]
+            result.append(search(trie, sorted(puzzle), 0, first, False))
+        return result
+
+
+# Time:  O(m*2^(L-1) + n*(l+m)), m is the number of puzzles, L is the length of puzzles
+#                              , n is the number of words, l is the max length of words
+# Space: O(m*2^(L-1))
+import collections
+
+
+class Solution2(object):
+    def findNumOfValidWords(self, words, puzzles):
+        """
+        :type words: List[str]
+        :type puzzles: List[str]
+        :rtype: List[int]
+        """
+        L = 7
+        lookup = collections.defaultdict(list)
+        for i in xrange(len(puzzles)):
+            bits = []
+            base = 1 << (ord(puzzles[i][0])-ord('a'))
+            for j in xrange(1, L):
+                bits.append(ord(puzzles[i][j])-ord('a'))
+            for k in xrange(2**len(bits)):
+                bitset = base
+                for j in xrange(len(bits)):
+                    if k & (1<<j):
+                        bitset |= 1<<bits[j]
+                lookup[bitset].append(i)
+        result = [0]*len(puzzles)
+        for word in words:
+            bitset = 0
+            for c in word:
+                bitset |= 1<<(ord(c)-ord('a'))
+            if bitset not in lookup:
+                continue
+            for i in lookup[bitset]:
+                result[i] += 1
+        return result