1822. Sign of the Product of an Array

Description of the Problem

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

Code (Rust)

impl Solution {
    pub fn array_sign(nums: Vec<i32>) -> i32 {
        nums
            .into_iter()
            .map( |a| if a < 0 { -1 } else if a > 0 { 1 } else { 0 } )
            .reduce(|a, b| a * b)
            .unwrap()
    }
}

Complexity

  • n is the number of elements in the array

Time complexity:

  • \( T(n) = \Theta(n) \)

Auxiliary Space:

  • \( S(n) = O(1) \)