Maximum of Absolute Value Expression — LeetCode 1131 Python Solution

The problem

Given two arrays of integers with equal lengths, return the maximum value of: |arr1[i] - arr1[j]| + |arr2[i] - arr2[j]| + |i - j| where the maximum is taken over all 0 <= i, j < arr1.length.

Example

Input

arr1 = [1,2,3,4], arr2 = [-1,4,5,6]

Output

13

Python solution

class Solution:
    def maxAbsValExpr(self, arr1: List[int], arr2: List[int]) -> int:
        dirs = (1, -1, -1, 1, 1)
        ans = -inf
        for a, b in pairwise(dirs):
            mx, mi = -inf, inf
            for i, (x, y) in enumerate(zip(arr1, arr2)):
                mx = max(mx, a * x + b * y + i)
                mi = min(mi, a * x + b * y + i)
                ans = max(ans, mx - mi)
        return ans

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 1131. Maximum of Absolute Value Expression is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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