思路

排序算法应用非常广泛，本题就是一道非常简单的归并排序应用。现在面试题应该很少直接出这么easy的了。

解法

class Solution {
    public String mergeAlternately(String word1, String word2) {
        int length1 = word1.length();
        int length2 = word2.length();
        StringBuilder sb = new StringBuilder();
        int i = 0, j = 0;
        while(i < length1 || j < length2) {
            if (i < length1) {
                sb.append(word1.charAt(i));
                i++;
            }
            if (j < length2) {
                sb.append(word2.charAt(j));
                j++;
            }
        }
        return sb.toString();
        
    }
}