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### How to Nail your next Technical Interview

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## 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
Help us know you better!

## How many years of coding experience do you have?

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

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Given a non-negative number as an integer array `digits`, where `digits[i]` represents `ith` digit of the given number. Add one to the number and return its digits array.

## Example One

``````{
"digits": "[4, 5, 6]"
}
``````

Output:

``````[4, 5, 7]
``````

number = 456
number + 1 = 457

## Example Two

``````{
"digits": "[9, 9]"
}
``````

Output:

``````[1, 0, 0]
``````

## Notes

• The digits are ordered from most significant to least significant in left-to-right order.
• The given number does not contain any leading zeros.

Constraints:

• 1 <= size of the `digits` array <= 104
• 0 <= any element of the `digits` array <= 9

## Code For Add One Solution: Iterative

``````
/*
Asymptotic complexity in terms of length of the given list \`n\`:
* Time: O(n).
* Auxiliary space: O(1).
* Total space: O(n).
*/

int n = digits.size();

int carry = 1;
for(int i = digits.size() - 1; i >= 0; i--){
int sum = digits[i] + carry;
carry = (sum >= 10) ? 1 : 0;
digits[i] = sum % 10;
}

if(carry != 0) {
// if carry is not zero append it to the beginning
digits.insert(digits.begin(), 1);
}
return digits;
}
``````

We hope that these solutions to the add one 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:

### Try yourself in the Editor

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

Given a non-negative number as an integer array `digits`, where `digits[i]` represents `ith` digit of the given number. Add one to the number and return its digits array.

## Example One

``````{
"digits": "[4, 5, 6]"
}
``````

Output:

``````[4, 5, 7]
``````

number = 456
number + 1 = 457

## Example Two

``````{
"digits": "[9, 9]"
}
``````

Output:

``````[1, 0, 0]
``````

## Notes

• The digits are ordered from most significant to least significant in left-to-right order.
• The given number does not contain any leading zeros.

Constraints:

• 1 <= size of the `digits` array <= 104
• 0 <= any element of the `digits` array <= 9

## Code For Add One Solution: Iterative

``````
/*
Asymptotic complexity in terms of length of the given list \`n\`:
* Time: O(n).
* Auxiliary space: O(1).
* Total space: O(n).
*/

int n = digits.size();

int carry = 1;
for(int i = digits.size() - 1; i >= 0; i--){
int sum = digits[i] + carry;
carry = (sum >= 10) ? 1 : 0;
digits[i] = sum % 10;
}

if(carry != 0) {
// if carry is not zero append it to the beginning
digits.insert(digits.begin(), 1);
}
return digits;
}
``````

We hope that these solutions to the add one 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: