Buddy Strings

Leetcode problem 859; Difficulty: Easy

Problem Statement

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".

Constraints:

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

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.

Example 4:

Input: s = "aaaaaaabc", goal = "aaaaaaacb"

Output: true

Submitted Solution

The implemented solution received the following rating on Leetcode: