1822. Sign of the Product of an Array
Description
Implement a function signFunc(x)
that returns:
1
ifx
is positive.-1
ifx
is negative.0
ifx
is equal to0
.
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
Solutions
Solution 1: Direct Traversal
The problem requires us to return the sign of the product of the array elements, i.e., return $1$ for positive numbers, $-1$ for negative numbers, and $0$ if it equals $0$.
We can define an answer variable ans
, initially set to $1$.
Then we traverse each element $v$ in the array. If $v$ is a negative number, we multiply ans
by $-1$. If $v$ is $0$, we return $0$ in advance.
After the traversal is over, we return ans
.
The time complexity is $O(n)$, where $n$ is the length of the array. The space complexity is $O(1)$.
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