Solved! Leetcode 2441. Largest Positive Integer That Exists With Its Negative

Description: Largest Positive Integer That Exists With Its Negative

Given an integer array nums that does not contain any zeros, find the largest positive integer k such that -k also exists in the array.

Return the positive integer k. If there is no such integer, return -1.

Example 1

<strong>Input:</strong> nums = [-1,2,-3,3]
<strong>Output:</strong> 3
<strong>Explanation:</strong> 3 is the only valid k we can find in the array.

Example 2

<strong>Input:</strong> nums = [-1,10,6,7,-7,1]
<strong>Output:</strong> 7
<strong>Explanation:</strong> Both 1 and 7 have their corresponding negative values in the array. 7 has a larger value.

Example 3

<strong>Input:</strong> nums = [-10,8,6,7,-2,-3]
<strong>Output:</strong> -1
<strong>Explanation:</strong> There is no a single valid k, we return -1.

Constraints

• 1 <= nums.length <= 1000
• -1000 <= nums[i] <= 1000
• nums[i] != 0

Solution

class Solution {
    //edge cases
    //[-30, -30]
    //[-30, 30, -30]
    //[-1, 1, -1, -1, -1]
    public int findMaxK(int[] nums) {
        int[] pos = new int[1001];
        int[] neg = new int[1001];
        for(int n: nums){
            if(n<0)
                neg[Math.abs(n)]++;
            else
                pos[n]++;
        }

        for(int i=1000;i>=1;i--){
            if(pos[i]>0 && neg[i]>0){
                return i;
            }
        }

        return -1;
    }
}

Time Complexity

O(1), fixed length array

Space Complexity

O(1)