Given two strings A and Bof lowercase letters, return true if and only if wecan swap two letters in A so that the result equals B.
Example 1:
Input: A = "ab", B = "ba"
Output: true
Example 2:
Input: A = "ab", B = "ab"
Output: false
Example 3:
Input: A = "aa", B = "aa"
Output: true
Example 4:
Input: A = "aaaaaaabc", B = "aaaaaaacb"
Output: true
Example 5:
Input: A = "", B = "aa"
Output: false
Note:
- 0 <= A.length <= 20000
- 0 <= B.length <= 20000
- A andB consist only of lowercase letters.
见程序注释