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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
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# Set Mismatch Problem Statement

You have a set of positive integers, which originally contains all the numbers from `1` to `n`. Unfortunately, due to some error, one of the numbers in the set got duplicated to another number in the set, which results in repetition of one number and loss of another number.

Given an integer array `numbers` representing the data status of this set after the error, find the number that occurs twice and the number that is missing and return them in the form of an array.

## Example One

``````{
"numbers": [5, 4, 2, 3, 5]
}
``````

Output:

``````[5, 1]
``````

## Example Two

``````{
"nums": [1, 1]
}
``````

Output:

``````[1, 2]
``````

## Notes

Return two integers in form of a list `[x, y]` where `x` represents the duplicated number and `y` represents the missing number.

Constraints:

• 2 <= size of the input list <= 105
• 1 <= any element of the input list <= 105

## Code For Set Mismatch Solution: Iterative

``````/*
Asymptotic complexity in terms of the number of elements in \`numbers\` \`n\`:
* Time: O(n).
* Auxiliary space: O(1).
* Total space: O(1).
*/

vector<int> find_error(vector<int> &numbers) {

for (int i : numbers) {
if (numbers[abs(i) - 1] < 0) {
}
else {
numbers[abs(i) - 1] *= -1;
}
}

for (int i = 0; i < int(numbers.size()); i++) {
if (numbers[i] > 0) {
}
}

}

``````

We hope that these solutions to the set mismatched 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.

# Set Mismatch Problem Statement

You have a set of positive integers, which originally contains all the numbers from `1` to `n`. Unfortunately, due to some error, one of the numbers in the set got duplicated to another number in the set, which results in repetition of one number and loss of another number.

Given an integer array `numbers` representing the data status of this set after the error, find the number that occurs twice and the number that is missing and return them in the form of an array.

## Example One

``````{
"numbers": [5, 4, 2, 3, 5]
}
``````

Output:

``````[5, 1]
``````

## Example Two

``````{
"nums": [1, 1]
}
``````

Output:

``````[1, 2]
``````

## Notes

Return two integers in form of a list `[x, y]` where `x` represents the duplicated number and `y` represents the missing number.

Constraints:

• 2 <= size of the input list <= 105
• 1 <= any element of the input list <= 105

## Code For Set Mismatch Solution: Iterative

``````/*
Asymptotic complexity in terms of the number of elements in \`numbers\` \`n\`:
* Time: O(n).
* Auxiliary space: O(1).
* Total space: O(1).
*/

vector<int> find_error(vector<int> &numbers) {

for (int i : numbers) {
if (numbers[abs(i) - 1] < 0) {
}
else {
numbers[abs(i) - 1] *= -1;
}
}

for (int i = 0; i < int(numbers.size()); i++) {
if (numbers[i] > 0) {
}
}

}

``````

We hope that these solutions to the set mismatched 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: