Merge Strings Alternately Python Solution

lcpy gen -n 1768   # by problem number
lcpy gen -s merge_strings_alternately   # by problem name

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

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

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

class Solution:
    # Time: O(n + m)
    # Space: O(n + m)
    def merge_alternately(self, word1: str, word2: str) -> str:
        result: list[str] = []
        i = 0
        n, m = len(word1), len(word2)

        while i < n or i < m:
            if i < n:
                result.append(word1[i])
            if i < m:
                result.append(word2[i])
            i += 1

        return "".join(result)