word1
을 우선적으로 배치하며, 번갈아오도록 word2
와 같이 병합function mergeAlternately(word1: string, word2: string): string {
let merged = ''
let i = 0
let j = 0
while(i < word1.length && j < word2.length) {
merged += word1[i]
merged += word2[j]
i++
j++
}
return merged + word1.slice(i) + word2.slice(j)
};