Leetcode: Word Pattern II

Word Pattern II



Similar Problems:


Given a pattern and a string str, find if str follows the same pattern.

Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty substring in str.

Examples:

  1. pattern = “abab”, str = “redblueredblue” should return true.
  2. pattern = “aaaa”, str = “asdasdasdasd” should return true.
  3. pattern = “aabb”, str = “xyzabcxzyabc” should return false.

Notes:
You may assume both pattern and str contains only lowercase letters.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.


## Blog link: https://code.dennyzhang.com/word-pattern-ii
## Basic Ideas:
##  In str, not all words are the same length
##
## Complexity:
class Solution(object):
    def wordPatternMatch(self, pattern, str):
        """
        :type pattern: str
        :type str: str
        :rtype: bool
        """
        len1, len2 = len(pattern), len(str)
        if len1 == 0 or len2 == 0: return len1 == len2
        # problematic?
        if len2%len1 != 0: return False
        word_len = len2/len1
        d, seen = {}, set([])
        for i in range(len1):
            ch = pattern[i]
            word = str[i*word_len:(i+1)*word_len]
            if ch in d:
                if d[ch] != word: return False
            else:
                if word in seen: return False
                d[ch] = word
                seen.add(word)
        return True
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