Compute a key value from a list of numbers using a repeated rule over adjacent values.
You are given an array of integers. Starting from the first element, compare neighboring values and derive a new value according to the problem's key rule. Continue processing the array until a single key value can be determined.
Your task is to return that final key. The exact transformation is intentionally framed as a practice exercise for careful array processing and arithmetic handling.
Input Format
- An integer array
nums. - The array length and the precise numeric range may vary by test case.
Output Format
- Return a single integer representing the computed key.
Constraints
- Assume the array contains at least one number.
- Use integer arithmetic.
- If multiple intermediate steps are involved, process them in the natural left-to-right order.
Example 1
Input
nums = [5, 2, 9, 1]
Output
1
Explanation
Illustrative example: apply the key rule across the numbers from left to right until a single value remains.
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.