Register for our webinar

How to Nail your next Technical Interview

1 hour
Loading...
1
Enter details
2
Select webinar slot
*Invalid Name
*Invalid Name
By sharing your contact details, you agree to our privacy policy.
Step 1
Step 2
Congratulations!
You have registered for our webinar
check-mark
Oops! Something went wrong while submitting the form.
1
Enter details
2
Select webinar slot
*All webinar slots are in the Asia/Kolkata timezone
Step 1
Step 2
check-mark
Confirmed
You are scheduled with Interview Kickstart.
Redirecting...
Oops! Something went wrong while submitting the form.
close-icon
Iks white logo

You may be missing out on a 66.5% salary hike*

Nick Camilleri

Head of Career Skills Development & Coaching
*Based on past data of successful IK students
Iks white logo
Help us know you better!

How many years of coding experience do you have?

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
Iks white logo

FREE course on 'Sorting Algorithms' by Omkar Deshpande (Stanford PhD, Head of Curriculum, IK)

Thank you! Please check your inbox for the course details.
Oops! Something went wrong while submitting the form.
closeAbout usWhy usInstructorsReviewsCostFAQContactBlogRegister for Webinar
Our June 2021 cohorts are filling up quickly. Join our free webinar to Uplevel your career
close

Add Strings Problem

Add Strings Problem Statement

Return sum of two given integers a and b in the string format.

Example

{
"a": "10",
"b": "20"
}

Output:

"30"

10 + 20 = 30, hence the output string will be "30"

Notes

  • The input string can have trailing zeros, but the output string should not have the trailing zeros.

  • We expect you to solve this problem without using any built-in library for handling large numbers.

Constraints:

  • 1 <= length of both the strings <= 105
  • a and b consist of only digits

Code For Add Strings Solution: Naive

/*
Asymptotic complexity in terms of the total length of input strings \`n\`:
* Time: O(n).
* Auxiliary space: O(n).
* Total space: O(n).
*/

string add_two_strings(string &a, string &b) {
    string answer;

    int i = a.size() - 1, j = b.size() - 1, carry = 0;

    // Loop till both the strings or carry is not processed.
    while (i >= 0 || j >= 0 || carry) {
        // Store the sum of the current digits(if exists) of both the strings with carry from the previous
        // stage.
        int currentSum = (i >= 0 ? a[i--] - '0' : 0) + (j >= 0 ? b[j--] - '0' : 0) + carry;

        answer.push_back((currentSum % 10) + '0');
        carry = currentSum / 10;
    }

    // Remove trailing zeros.
    while (answer.size() > 1 and answer.back() == '0') {
        answer.pop_back();
    }

    reverse(answer.begin(), answer.end());
    return answer;
}

We hope that these solutions to the Add Strings Problem have helped you level up your coding skills. You can expect problems like these at top tech companies like Amazon and Google.

If you are preparing for a tech interview at FAANG or any other Tier-1 tech company, register for Interview Kickstart’s FREE webinar to understand the best way to prepare.

Interview Kickstart offers interview preparation courses taught by FAANG+ tech leads and seasoned hiring managers. Our programs include a comprehensive curriculum, unmatched teaching methods, and career coaching to help you nail your next tech interview.

We offer 18 interview preparation courses, each tailored to a specific engineering domain or role, including the most in-demand and highest-paying domains and roles, such as:

‍To learn more, register for the FREE webinar.

Try yourself in the Editor

Note: Input and Output will already be taken care of.

Add Strings Problem

Add Strings Problem Statement

Return sum of two given integers a and b in the string format.

Example

{
"a": "10",
"b": "20"
}

Output:

"30"

10 + 20 = 30, hence the output string will be "30"

Notes

  • The input string can have trailing zeros, but the output string should not have the trailing zeros.

  • We expect you to solve this problem without using any built-in library for handling large numbers.

Constraints:

  • 1 <= length of both the strings <= 105
  • a and b consist of only digits

Code For Add Strings Solution: Naive

/*
Asymptotic complexity in terms of the total length of input strings \`n\`:
* Time: O(n).
* Auxiliary space: O(n).
* Total space: O(n).
*/

string add_two_strings(string &a, string &b) {
    string answer;

    int i = a.size() - 1, j = b.size() - 1, carry = 0;

    // Loop till both the strings or carry is not processed.
    while (i >= 0 || j >= 0 || carry) {
        // Store the sum of the current digits(if exists) of both the strings with carry from the previous
        // stage.
        int currentSum = (i >= 0 ? a[i--] - '0' : 0) + (j >= 0 ? b[j--] - '0' : 0) + carry;

        answer.push_back((currentSum % 10) + '0');
        carry = currentSum / 10;
    }

    // Remove trailing zeros.
    while (answer.size() > 1 and answer.back() == '0') {
        answer.pop_back();
    }

    reverse(answer.begin(), answer.end());
    return answer;
}

We hope that these solutions to the Add Strings Problem have helped you level up your coding skills. You can expect problems like these at top tech companies like Amazon and Google.

If you are preparing for a tech interview at FAANG or any other Tier-1 tech company, register for Interview Kickstart’s FREE webinar to understand the best way to prepare.

Interview Kickstart offers interview preparation courses taught by FAANG+ tech leads and seasoned hiring managers. Our programs include a comprehensive curriculum, unmatched teaching methods, and career coaching to help you nail your next tech interview.

We offer 18 interview preparation courses, each tailored to a specific engineering domain or role, including the most in-demand and highest-paying domains and roles, such as:

‍To learn more, register for the FREE webinar.

Worried About Failing Tech Interviews?

Attend our free webinar to amp up your career and get the salary you deserve.

Ryan-image
Hosted By
Ryan Valles
Founder, Interview Kickstart
blue tick
Accelerate your Interview prep with Tier-1 tech instructors
blue tick
360° courses that have helped 14,000+ tech professionals
blue tick
100% money-back guarantee*
Register for Webinar
All Blog Posts