LeetCode Entry
2441. Largest Positive Integer That Exists With Its Negative
Max number that has its negative in array pointers
2441. Largest Positive Integer That Exists With Its Negative easy
blog post
substack
youtube
Join me on Telegram
https://t.me/leetcode_daily_unstoppable/590
Problem TLDR
Max number that has its negative in array #easy #two_pointers
Intuition
One possible solution is to sort array and compare minimums with maximums by moving two pointers from left and right of the array. Another way is to remember which numbers are seen and choose the maximum of them.
Approach
- For the second solution, we can use just a [2000] array, as the total count is not that big.
Complexity
-
Time complexity: \(O(nlog(n))\) and \(O(n)\)
-
Space complexity: \(O(1)\) and \(O(n)\)
Code
fun findMaxK(nums: IntArray): Int {
nums.sort()
var i = 0; var j = nums.lastIndex
while (i < j)
if (nums[i] == -nums[j]) return nums[j]
else if (-nums[i] < nums[j]) j-- else i++
return -1
}
pub fn find_max_k(nums: Vec<i32>) -> i32 {
let (mut counts, mut res) = (vec![0; 2001], -1);
for x in nums {
if counts[1000 - x as usize] > 0 { res = res.max(x.abs()) }
counts[x as usize + 1000] += 1
}; res
}