LeetCode75——Day1

一、题目

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.

二、题解

class Solution {
public:
    string mergeAlternately(string word1, string word2) {
      int n1 = word1.length();
      int n2 = word2.length();
      int i = 0,j = 0;
      string res;
      while(i < n1 && j < n2){
        res += word1[i++];
        res += word2[j++];
      }
      while(i < n1) res += word1[i++];
      while(j < n2) res += word2[j++];
      return res;
    }
};