The longest subarray length with a positive product of 1567 recorded by leecode

topic

Give you an array of integers nums , Please find the length of the longest subarray whose product is positive .

The subarray of an array is an array of zero or more consecutive numbers in the original array .

Please return the length of the longest subarray whose product is a positive number .

Example 1：

Input ：nums = [1,-2,-3,4]
Output ：4
explain ： The product of the array itself is a positive number , The value is 24 .
Example 2：

Input ：nums = [0,1,-2,-3,-4]
Output ：3
explain ： The subarray with the longest positive product is [1,-2,-3] , The product is 6 .
Be careful , We can't 0 Also included in the subarray , Because the product is 0 , Not positive. .
Example 3：

Input ：nums = [-1,-2,-3,0,1]
Output ：2
explain ： The longest subarray whose product is a positive number is [-1,-2] perhaps [-2,-3] .

Tips ：

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

answer

class Solution {
    
    public int getMaxLen(int[] nums) {
    
        List<List<Integer>> lists = new ArrayList<>();
        List<Integer> temp = new ArrayList<>();
        lists.add(temp);
        for(int i = 0;i < nums.length;i++){
    
            if(nums[i] != 0){
    
                temp.add(nums[i]);
            }else{
    
                if(temp.size() != 0){
    
                    lists.add(copy(temp));
                    temp = new ArrayList<>();
                    lists.add(temp);
                }
            }
        }
        int res = 0;
        for(List<Integer> list : lists){
    
            int min = -1;
            int max = -1;
            int count = 0;
            boolean isFirst = true;
            int i = 0;
            while(i < list.size()){
    
                if(list.get(i) < 0){
    
                    count++;
                    if(isFirst){
    
                        min = i;
                        isFirst = false;
                        max = i;
                    }else{
    
                        max = i;
                    }
                }
                i++;
            }
            if(count % 2 != 0){
    
                int ex = Math.min(min + 1,list.size() - max);
                res = Math.max(res,list.size() - ex);
            }else{
    
                res = Math.max(res,list.size());
            }
        }
        return res;
    }
    
    private List<Integer> copy(List<Integer> src){
    
        List<Integer> copy = new ArrayList<>();
        for(int i : src){
    
            copy.add(i);
        }
        return copy;
    }
}