Merge strings alternately

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

Solution:

Intuition
Extremely simple problem. In some ways similar to merging 2 sorted arrays, but without the conditional check. (and only one pointer is needed).

Implementation

def merge_strings(word1, word2):
	merged = ''
	i = 0
	while i < len(word1) and i < len(word2):
		merged += word1[i] + word2[i]
		i += 1
	if i < len(word1):
		merged += word1[i:]
	if i < len(word2):
		merged += word2[i:]
	return merged
	
#time: o(n+m)
#memory: o(1)

Review 1
Not a huge fan of the above implementation. There is no need to treat word1 so generically. Just iterate over it and add the remainder from word2 if it exists.

def merge_strings(word1, word2):
	res = ''
	for i in range(len(word1)):
		res += word1[i]
		if i < len(word2):
			res += word2[i]
	return res + word2[i+1:]

review