1567. Maximum Length of Subarray With Positive Product
Medium44.6% acceptance110,241 / 246,988 submissions
Asked by 2 companies
Topics
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 <= 105-109 <= nums[i] <= 109
Hints
Hint 1
Split the whole array into subarrays by zeroes since a subarray with positive product cannot contain any zero.
Hint 2
If the subarray has even number of negative numbers, the whole subarray has positive product.
Hint 3
Otherwise, we have two choices, either - remove the prefix till the first negative element in this subarray, or remove the suffix starting from the last negative element in this subarray.