LeetCode 205. Isomorphic Strings

Title address (205. Isomorphic Strings )

https://leetcode-cn.com/problems/isomorphic-strings/

Title Description

 Given two strings  s  and  t, Judge whether they are isomorphic .

 If  s  The characters in can be replaced according to some mapping relationship  t , So these two strings are isomorphic .

 Every character that appears should be mapped to another character , Without changing the order of characters . Different characters cannot be mapped to the same character , The same character can only be mapped to the same character , Characters can be mapped to themselves .

 

 Example  1:

 Input ：s = "egg", t = "add"
 Output ：true


 Example  2：

 Input ：s = "foo", t = "bar"
 Output ：false

 Example  3：

 Input ：s = "paper", t = "title"
 Output ：true

 

 Tips ：

 It can be assumed  s  and  t  Same length .

Ideas

Use the dictionary to traverse whether it corresponds

Code

• Language support ：Python3

Python3 Code:

class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        resDict = dict()
        for index,val in enumerate(s):
            if val in resDict:
                if resDict[val] != t[index]:
                    return False
            else:
                resDict[val] = t[index]
        resDict = dict()
        for index,val in enumerate(t):
            if val in resDict:
                if resDict[val] != s[index]:
                    return False
            else:
                resDict[val] = s[index]
        return True

Complexity analysis

Make n Is array length .

• Time complexity ：$O(n)$
• Spatial complexity ：$O(n)$