public class Solution
extends Object
389 - Find the Difference\.
Easy
You are given two strings `s` and `t`.
String `t` is generated by random shuffling string `s` and then add one more letter at a random position.
Return the letter that was added to `t`.
**Example 1:**
**Input:** s = "abcd", t = "abcde"
**Output:** "e"
**Explanation:** 'e' is the letter that was added.
**Example 2:**
**Input:** s = "", t = "y"
**Output:** "y"
**Example 3:**
**Input:** s = "a", t = "aa"
**Output:** "a"
**Example 4:**
**Input:** s = "ae", t = "aea"
**Output:** "a"
**Constraints:**
* `0 <= s.length <= 1000`
* `t.length == s.length + 1`
* `s` and `t` consist of lower-case English letters.