MaximumLengthofSubarrayWithPositiveProduct.java

/*
 * 1567. Maximum Length of Subarray With Positive Product
Medium
Topics
Companies
Hint
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:

1 <= nums.length <= 10^5
-10^9 <= nums[i] <= 10^9
 */

public class MaximumLengthofSubarrayWithPositiveProduct {
    public static void main(String[] args) {
        
    }
}

class Solution {
    public int getMaxLen(int[] nums) {
        int max=0,  s, e, firstNegative=-1, lastNegative=-1; 
        boolean positive = true;

        for (int i = 0; i < nums.length; i++) {
            s=i;
            while (i < nums.length && nums[i] !=0) {
                if (nums[i]<0) {
                    if (firstNegative < s) {
                        firstNegative =i;
                    }
                    lastNegative = i;
                    positive = !positive;   
                }
                i++;
            }
            e = i-1;

            if (positive) {
                max =  Math.max(max, (e-s+1));
            } else {
                max = Math.max(max, (e-s - Math.min((firstNegative-s) , (e-lastNegative) )));
                positive = true;
            }
        }
        return max;
    }
}