Leetcode #2529: Maximum Count of Positive Integer and Negative Integer
In this guide, we solve Leetcode #2529 Maximum Count of Positive Integer and Negative Integer in Python and focus on the core idea that makes the solution efficient.
You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.
Problem Statement
Given an array nums sorted in non-decreasing order, return the maximum between the number of positive integers and the number of negative integers. In other words, if the number of positive integers in nums is pos and the number of negative integers is neg, then return the maximum of pos and neg.
Quick Facts
- Difficulty: Easy
- Premium: No
- Tags: Array, Binary Search, Counting
Intuition
The problem structure suggests a monotonic decision, which makes binary search a natural fit.
By halving the search space each step, we reach the answer efficiently.
Approach
Search either directly on a sorted array or on the answer space using a check function.
Each check is fast, and the logarithmic search keeps the overall runtime low.
Steps:
- Define the search bounds.
- Check the mid point condition.
- Narrow the bounds until convergence.
Example
Input: nums = [-2,-1,-1,1,2,3]
Output: 3
Explanation: There are 3 positive integers and 3 negative integers. The maximum count among them is 3.
Python Solution
class Solution:
def maximumCount(self, nums: List[int]) -> int:
a = sum(x > 0 for x in nums)
b = sum(x < 0 for x in nums)
return max(a, b)
Complexity
The time complexity is , where is the length of the array. The space complexity is .
Edge Cases and Pitfalls
Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.
Summary
This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.