Rotate Function — LeetCode 396 Python Solution

The problem

You are given an integer array nums of length n. Assume arrk to be an array obtained by rotating nums by k positions clock-wise.

Example

Input

nums = [4,3,2,6]

Output

26

Explanation

F(0) = (0 * 4) + (1 * 3) + (2 * 2) + (3 * 6) = 0 + 3 + 4 + 18 = 25

Python solution

class Solution:
    def maxRotateFunction(self, nums: List[int]) -> int:
        f = sum(i * v for i, v in enumerate(nums))
        n, s = len(nums), sum(nums)
        ans = f
        for i in range(1, n):
            f = f + s - n * nums[n - i]
            ans = max(ans, f)
        return ans

Complexity

Pattern: Dynamic Programming

Define a state, write the transition, and stop recomputing the same subproblem. LeetCode 396. Rotate Function is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Dynamic Programming.

The dynamic programming guide has the Python template for the pattern and the 481 LeetCode problems that use it.

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