Brooke

一、題目

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.

 

二、程式作法

public class Solution
{
    public string MergeAlternately(string word1, string word2)
    {
        string res = "";
        int idx = 0;
        while (idx < word1.Length && idx < word2.Length)
        {
            res += word1[idx].ToString() + word2[idx].ToString();
            idx++;
        }
        if (word1.Length < word2.Length)
            res += word2.Substring(idx);
        if (word1.Length > word2.Length)
            res += word1.Substring(idx);
        return res;
    }
}

 

三、思路筆記

略