LeetCode 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.

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这题真没啥难度，就是简单的merge两个string/array。

然而自己傻了，想复杂了，其实一个if里两个前后append就完事了，我还在那用了个boolean flag来控制每次放哪个……

class Solution {
    public String mergeAlternately(String word1, String word2) {
        StringBuilder sb = new StringBuilder();
        int p1 = 0;
        int p2 = 0;
        while (p1 < word1.length() && p2 < word2.length()) {
            sb.append(word1.charAt(p1));
            sb.append(word2.charAt(p2));
            p1++;
            p2++;
        }
        while (p1 < word1.length()) {
            sb.append(word1.charAt(p1));
            p1++;
        }
        while (p2 < word2.length()) {
            sb.append(word2.charAt(p2));
            p2++;
        }
        return sb.toString();
    }
}