Sign of the Product of an Array — LeetCode 1822 Python Solution

The problem

Implement a function signFunc(x) that returns: 1 if x is positive. -1 if x is negative.

Example

Input

nums = [-1,-2,-3,-4,3,2,1]

Output

1

Explanation

The product of all values in the array is 144, and signFunc(144) = 1

Python solution

class Solution:
    def arraySign(self, nums: List[int]) -> int:
        ans = 1
        for v in nums:
            if v == 0:
                return 0
            if v < 0:
                ans *= -1
        return ans

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 1822. Sign of the Product of an Array 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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