Create substring_with_concatenation_of_all_words.py

Author: avidLearnerInProgress

substring_with_concatenation_of_all_words.py

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+from collections import Counter, defaultdict
+
+class Solution(object):
+    def findSubstring(self, s, words):
+        """
+        :type s: str
+        :type words: List[str]
+        :rtype: List[int]
+        """
+        wordBag = Counter(words)   # count the freq of each word
+        wordLen, numWords = len(words[0]), len(words)
+        totalLen, res = wordLen*numWords, []
+        for i in range(len(s)-totalLen+1):   # scan through s
+            # For each i, determine if s[i:i+totalLen] is valid
+            seen = defaultdict(int)   # reset for each i
+            for j in range(i, i+totalLen, wordLen):
+                currWord = s[j:j+wordLen]
+                if currWord in wordBag:
+                    seen[currWord] += 1
+                    if seen[currWord] > wordBag[currWord]:
+                        break
+                else:   # if not in wordBag
+                    break    
+            if seen == wordBag:
+                res.append(i)   # store result
+        return res