LeetCode-in-Java

1567. Maximum Length of Subarray With Positive Product

Medium

Given an array of integers nums, find the maximum length of a subarray where the product of all its elements is positive.

A subarray of an array is a consecutive sequence of zero or more values taken out of that array.

Return the maximum length of a subarray with positive product.

Example 1:

Input: nums = [1,-2,-3,4]

Output: 4

Explanation: The array nums already has a positive product of 24.

Example 2:

Input: nums = [0,1,-2,-3,-4]

Output: 3

Explanation: The longest subarray with positive product is [1,-2,-3] which has a product of 6. Notice that we cannot include 0 in the subarray since that’ll make the product 0 which is not positive.

Example 3:

Input: nums = [-1,-2,-3,0,1]

Output: 2

Explanation: The longest subarray with positive product is [-1,-2] or [-2,-3].

Constraints:

Solution

public class Solution {
    public int getMaxLen(int[] nums) {
        int posLen = 0;
        int negLen = 0;
        int res = 0;
        for (int num : nums) {
            if (num == 0) {
                posLen = 0;
                negLen = 0;
            } else if (num > 0) {
                posLen++;
                negLen = negLen == 0 ? 0 : negLen + 1;
            } else {
                int temp = posLen;
                posLen = negLen == 0 ? 0 : negLen + 1;
                negLen = temp + 1;
            }
            res = Math.max(res, posLen);
        }
        return res;
    }
}