Formatted question description: https://leetcode.ca/all/1822.html

1822. Sign of the Product of an Array

Level

Easy

Description

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

Solution

Loop over nums. If a zero is found, return 0. Otherwise, count the number of negative numbers. If the number of negative numbers is even, return 1. Otherwise, return -1.

  • class Solution {
        public int arraySign(int[] nums) {
            int negativeCount = 0;
            for (int num : nums) {
                if (num < 0)
                    negativeCount++;
                else if (num == 0)
                    return 0;
            }
            return negativeCount % 2 == 0 ? 1 : -1;
        }
    }
    
  • // OJ: https://leetcode.com/problems/sign-of-the-product-of-an-array/
    // Time: O(N)
    // Space: O(1)
    class Solution {
    public:
        int arraySign(vector<int>& A) {
            int cnt = 0;
            for (int n : A) {
                if (n == 0) return 0;
                cnt += n < 0;
            }
            return cnt % 2 ? -1 : 1;
        }
    };
    
  • # 1822. Sign of the Product of an Array
    # https://leetcode.com/problems/sign-of-the-product-of-an-array/
    
    class Solution:
        def arraySign(self, nums: List[int]) -> int:
            res = 1
            
            for num in nums:
                res *= num
            
            if res == 0: return 0
            elif res > 0 : return 1
            else: return -1
    
    

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