9/17 每日一題(檢查s是否可以透過調換順序變成goal)

 Given two strings s and goal, return true if you can swap two letters in s so the result is equal to goal, otherwise, return false.

Swapping letters is defined as taking two indices i and j (0-indexed) such that i != j and swapping the characters at s[i] and s[j].

• For example, swapping at indices 0 and 2 in "abcd" results in "cbad".

 

Example 1:

Input: s = "ab", goal = "ba"
Output: true
Explanation: You can swap s[0] = 'a' and s[1] = 'b' to get "ba", which is equal to goal.

Example 2:

Input: s = "ab", goal = "ab"
Output: false
Explanation: The only letters you can swap are s[0] = 'a' and s[1] = 'b', which results in "ba" != goal.

Example 3:

Input: s = "aa", goal = "aa"
Output: true
Explanation: You can swap s[0] = 'a' and s[1] = 'a' to get "aa", which is equal to goal.

 

Constraints:

• 1 <= s.length, goal.length <= 2 * 104
• s and goal consist of lowercase letters.

class Solution:

    def buddyStrings(self, s: str, goal: str) -> bool:

        if s==goal:

            '檢查有沒有交換空間'

            '如果字母數量=長度,那就沒有'

            if len(set(s))==len(s):

                return False

            else:

                return True

        else:

            s=list(s)

            goal=list(goal)

            n=0

            err_index=[]

            for i,j in zip(s,goal):

               

                if i != j:

                    err_index.append(n)

                n+=1

            if err_index:

       

                s[err_index[0]],s[err_index[-1]]=s[err_index[-1]],s[err_index[0]]

            return s == goal