10/9 每日一題(所有非英文字母的順序固定不變, 英文字母全部顛倒, stack)

Given a string s, reverse the string according to the following rules:

• All the characters that are not English letters remain in the same position.
• All the English letters (lowercase or uppercase) should be reversed.

Return s after reversing it.

 

Example 1:

Input: s = "ab-cd"
Output: "dc-ba"

Example 2:

Input: s = "a-bC-dEf-ghIj"
Output: "j-Ih-gfE-dCba"

Example 3:

Input: s = "Test1ng-Leet=code-Q!"
Output: "Qedo1ct-eeLg=ntse-T!"

 

Constraints:

• 1 <= s.length <= 100
• s consists of characters with ASCII values in the range [33, 122].
• s does not contain '\"' or '\\'.

 class Solution:

    def reverseOnlyLetters(self, s: str) -> str:

        stack=[]

        sym=[]

        for i in s:

            if i.isalpha():

                stack.append(i)

            else:

                sym.append(i)

        print(f'stack={stack}')

        res=[]

        letter=''

        for i,ele in enumerate(s):

            if ele.isalpha():

                letter+=stack.pop()

            else:

                res.append(letter)

                letter=''

        res.append(letter)

        result=''

        n=0

        for i in res:

            result +=i

            if n < len(sym):

                result+=sym[n]

                n+=1

        if n < len(sym):

            result+=sym[n]

            n+=1

        return result

----------------

class Solution:
    def reverseOnlyLetters(self, s: str) -> str:
        l,r= 0 , len(s)-1
        s = list(s)
        while l<r:
            while not s[l].isalpha() and l<r:
                l+=1
            while not s[r].isalpha() and l<r:
                r-=1
            s[l],s[r] = s[r],s[l]
            l+=1
            r-=1
        return "".join(s)

       

       

       

-----------------------

class Solution:
    def reverseOnlyLetters(self, s: str) -> str:
        letters = [i for i in s if i.isalpha()][::-1]
        for ind,ch in enumerate(s):
            if not ch.isalpha():
                letters.insert(ind,ch)
        return "".join(letters)