Today I have done leetcode's May LeetCoding Challenge with cpp.

May LeetCoding Challenge 2

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:

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

Example 2:

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

Example 3:

Input: nums = [-10,8,6,7,-2,-3]
Output: -1
Explanation: 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 {
public:
  int findMaxK(vector<int>& nums) {
    int count[2001] = {};
    for(auto n : nums) {
      count[n + 1000] += 1;
    }
    for(int i = 2000; i > 1000; --i) {
      if(count[2000 - i] && count[i]) return i - 1000;
    }
    return -1;
  }
};