1822-sign-of-the-product-of-an-array.rb

# frozen_string_literal: true

# 1822. Sign of the Product of an Array
# https://leetcode.com/problems/sign-of-the-product-of-an-array
# Easy

=begin
There is a function signFunc(x) that returns:

* 1 if x is positive.
* -1 if x is negative.
* 0 if x is equal to 0.
You are given an integer array nums. Let product be the product of all values in the array nums.

Return signFunc(product).

Example 1:
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

Example 2:
Input: nums = [1,5,0,2,-3]
Output: 0
Explanation: The product of all values in the array is 0, and signFunc(0) = 0

Example 3:
Input: nums = [-1,1,-1,1,-1]
Output: -1
Explanation: The product of all values in the array is -1, and signFunc(-1) = -1

Constraints:
* 1 <= nums.length <= 1000
* -100 <= nums[i] <= 100
=end

# @param {Integer[]} nums
# @return {Integer}
def array_sign(nums)
  nums.reduce(1) { _1 * (_2 <=> 0) }
end

# **************** #
#       TEST       #
# **************** #

require "test/unit"
class Test_array_sign < Test::Unit::TestCase
  def test_
    assert_equal 1, array_sign([-1, -2, -3, -4, 3, 2, 1])
    assert_equal 0, array_sign([1, 5, 0, 2, -3])
    assert_equal(-1, array_sign([-1, 1, -1, 1, -1]))
  end
end