290. Word Pattern

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 word in str.

Example 1:

Input: pattern = "abba", str = "dog cat cat dog" Output: true Example 2:

Input:pattern = "abba", str = "dog cat cat fish" Output: false Example 3:

Input: pattern = "aaaa", str = "dog cat cat dog" Output: false Example 4:

Input: pattern = "abba", str = "dog dog dog dog" Output: false Notes: You may assume pattern contains only lowercase letters, and str contains lowercase letters that may be separated by a single space.

思路：用" "分割字符串str，得到数组strArr， 用value遍历pattern，字典dic用来存pattern的元素value对应的strArr的元素，如果dic[value]有值，判断新旧值是否相等，不相等返回false，遍历完用集合set过滤下dic的values，看是否有重复，有重复返回false，否则true 代码：python3

class Solution:
    def wordPattern(self, pattern: str, str: str) -> bool:
        strArr=str.split(" ")
        if len(pattern) != len(strArr):
            return False
        dic={}
        print(dic)
        for index,value in enumerate(pattern):            
            if value in dic:
                if dic[value] != strArr[index]:
                    return False
            else:
                dic[value]= strArr[index]
        s = set(dic.values())
        if len(s) != len(dic.values()):
            return False
        else:
            return True