1002. Find Common Characters

https://leetcode.com/problems/find-common-characters

Description

Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order.

Example 1:

**Input:** words = ["bella","label","roller"]
**Output:** ["e","l","l"]

Example 2:

**Input:** words = ["cool","lock","cook"]
**Output:** ["c","o"]

Constraints:

• 1 <= words.length <= 100

• 1 <= words[i].length <= 100

• words[i] consists of lowercase English letters.

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