Rotate Function

MediumMathmath

Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.

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Problem

Given an integer array nums of length n, let arr_k be nums rotated clockwise by k positions (the last k elements move to the front). Define the rotation function F(k) = 0 * arr_k[0] + 1 * arr_k[1] + ... + (n - 1) * arr_k[n - 1]. Return the maximum of F(0), F(1), ..., F(n - 1). The answer fits in a signed 32-bit integer. An O(n) solution is expected.

Examples

Input: nums = [4,3,2,6]
Output: 26
F(0) = 25, F(1) = 16, F(2) = 23, F(3) = 26; the maximum is 26.
Input: nums = [100]
Output: 0
With one element every term is multiplied by 0.

Constraints

  • 1 <= nums.length <= 10^5
  • -100 <= nums[i] <= 100
  • The answer fits in a signed 32-bit integer

What the interviewer grades

A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.

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