[E].[J].1768.MergeStringsAlternately

class Solution {
    public String mergeAlternately(String word1, String word2) {
        StringBuilder r = new StringBuilder();
        int i = 0;
        while (i < Math.min(word1.length(), word2.length())){
            r.append(word1.charAt(i)).append(word2.charAt(i));
            i++;
        }
        if (word1.length() < word2.length()){
            for (int j = i; j < word2.length(); j++) {
                r.append(word2.charAt(j));
            }
        } else if (word1.length() > word2.length()) {
            for (int j = i; j < word1.length(); j++) {
                r.append(word1.charAt(j));
            }
        }
        
        return r.toString();
    }
}