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.

Solutions

class Solution {
public:
    string mergeAlternately(string word1, string word2) {
        int l1 = word1.size(), l2 = word2.size();
        string res;
        while (l1 || l2) {
            if (l1 > 0)
                res += word1[word1.size() - l1--];
            if (l2 > 0)
                res += word2[word2.size() - l2--];
        }
        return res;
    }
};