Merge strings alternately

class Solution:
    def mergeAlternately(self, word1: str, word2: str) -> str:
        res = ""
        i, j = 0, 0
        while i < len(word1) and j < len(word2):
            res += word1[i]
            i += 1
            res += word2[j]
            j += 1
        while i < len(word1):
            res += word1[i]
            i += 1
        while j < len(word2):
            res += word2[j]
            j += 1
        return res

Merge Strings Alternately

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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.