LeetCode 1153. String Transforms Into Another String 替換問題坑

Given two strings str1 and str2 of the same length, determine whether you can transform str1 into str2 by doing zero or more conversions.

In one conversion you can convert all occurrences of one character in str1 to any other lowercase English character.

Return true if and only if you can transform str1 into str2.

 

Example 1:

Input: str1 = "aabcc", str2 = "ccdee"
Output: true
Explanation: Convert 'c' to 'e' then 'b' to 'd' then 'a' to 'c'. Note that the order of conversions matter.

Example 2:

Input: str1 = "leetcode", str2 = "codeleet"
Output: false
Explanation: There is no way to transform str1 to str2.

 

Note:

1. 1 <= str1.length == str2.length <= 10^4
2. Both str1 and str2 contain only lowercase English letters.

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思路不難，但是不容易寫對，坑就是需要一個沒有被佔用的字母

class Solution:
    def canConvert(self, str1: str, str2: str) -> bool:
        dic = {}
        if (str1 == str2):
            return True
        l = len(str1)
        for i in range(l):
            if (str1[i] != str2[i]):
                if str1[i] in dic and dic[str1[i]] != str2[i]:
                    return False
                else:
                    dic[str1[i]] = str2[i]
        # bug1: return True if len(dic) < 26 or len(set(dic.values())) < 26 else False
        return len(set(str2)) < 26