0389. Find the Difference

https://leetcode.com/problems/find-the-difference

Description

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.

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