LeetCode 1822. Sign of the Product of an Array Solution in Java, C++, Python & More | Explanation + Code

Description

Implement 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

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).

PythonJavaC++GoRustJavaScriptC

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(code-box)

class Solution { public int arraySign(int[] nums) { int ans = 1; for (int v : nums) { if (v == 0) { return 0; } if (v < 0) { ans *= -1; } } return ans; } }(code-box)

class Solution { public: int arraySign(vector<int>& nums) { int ans = 1; for (int v : nums) { if (!v) return 0; if (v < 0) ans *= -1; } return ans; } };(code-box)

func arraySign(nums []int) int { ans := 1 for _, v := range nums { if v == 0 { return 0 } if v < 0 { ans *= -1 } } return ans }(code-box)

impl Solution { pub fn array_sign(nums: Vec<i32>) -> i32 { let mut ans = 1; for &num in nums.iter() { if num == 0 { return 0; } if num < 0 { ans *= -1; } } ans } }(code-box)

/** * @param {number[]} nums * @return {number} */ var arraySign = function (nums) { let ans = 1; for (const v of nums) { if (!v) { return 0; } if (v < 0) { ans *= -1; } } return ans; };(code-box)

int arraySign(int* nums, int numsSize) { int ans = 1; for (int i = 0; i < numsSize; i++) { if (nums[i] == 0) { return 0; } if (nums[i] < 0) { ans *= -1; } } return ans; }(code-box)