## 1. Problem

1768. Merge Strings Alternately

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.

## 2. Solution

I solved this problem like this.

- Complexity
- Time complexity : O(N)
- Space complexity : O(N)

- Step
- Using zip and append string to answer.

```
class Solution:
def mergeAlternately(self, word1: str, word2: str) -> str:
answer = ""
min_size = min(len(word1), len(word2))
for x, y in zip(word1, word2):
answer += x + y
return answer + word1[min_size:] + word2[min_size:]
```