1768. Merge Strings Alternately

https://leetcode.com/problems/merge-strings-alternately

Description

You are given two strings word1 and word2. Merge the strings by adding letters in alternating order, starting with word1. If a string is longer than the other, append the additional letters onto the end of the merged string.

Return the merged string.

Example 1:

**Input:** word1 = "abc", word2 = "pqr"
**Output:** "apbqcr"
**Explanation:** The merged string will be merged as so:
word1:  a   b   c
word2:    p   q   r
merged: a p b q c r

Example 2:

**Input:** word1 = "ab", word2 = "pqrs"
**Output:** "apbqrs"
**Explanation:** Notice that as word2 is longer, "rs" is appended to the end.
word1:  a   b 
word2:    p   q   r   s
merged: a p b q   r   s

Example 3:

**Input:** word1 = "abcd", word2 = "pq"
**Output:** "apbqcd"
**Explanation:** Notice that as word1 is longer, "cd" is appended to the end.
word1:  a   b   c   d
word2:    p   q 
merged: a p b q c   d

Constraints:

• 1 <= word1.length, word2.length <= 100

• word1 and word2 consist of lowercase English letters.

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