Merge Strings Alternately · Interview Problem

Back to problems

Leetcode

Easy

Strings

Arrays

Merge Strings Alternately

Build a new string by taking characters alternately from two input strings.

Acceptance 0%

Start Practice

Problem Statement

Problem

Given two strings, construct a new string by alternating characters from the first and second strings, starting with the first string.

Take the first character from the first string, then the first character from the second string.
Continue alternating characters from each string.
If one string runs out of characters first, append the remaining characters from the other string to the end.

Return the merged string.

This is a straightforward string-building problem that tests careful indexing and simulation.

Input Format

Two strings word1 and word2.
Each string contains lowercase English letters.

Output Format

Return a single string formed by alternating characters from word1 and word2.

Constraints

$0 \le |word1|, |word2|$
Strings contain only lowercase English letters.
The result length is $|word1| + |word2|$ .

Examples

Sample cases returned by the problem API.

Example 1

Input

word1 = "abc", word2 = "pqr"

Output

"apbqcr"

Explanation

Take a from word1, p from word2, b from word1, q from word2, c from word1, r from word2.

Example 2

Input

word1 = "ab", word2 = "pqrs"

Output

"apbqrs"

Explanation

Alternate until word1 ends, then append the remaining characters from word2.

Show 1 more example

Example 3

Input

word1 = "abcd", word2 = "pq"

Output

"apbqcd"

Explanation

Alternate until word2 ends, then append the remaining characters from word1.

Premium problem context

Unlock deeper context for this problem

Premium adds guided hints, editorial links, similar variants, discussion resources, and concept maps so you can understand why a problem matters, not just solve it once.

Guided hints

Editorial and discussion links

Concept map and variants

Track your progress