Count Odd Numbers in an Interval Range

LeetCode 1523, Easy. Topics: Math. View on LeetCode. Generate this problem as a practice environment: tested reference solution, 22 parametrized pytest cases, and a playground notebook:

lcpy gen -n 1523   # by problem number
lcpy gen -s count_odd_numbers_in_an_interval_range   # by problem name

Problem

Given two non-negative integers low and high. Return the count of odd numbers between low and high (inclusive).

Input: low = 3, high = 7
Output: 3
Explanation: The odd numbers between 3 and 7 are [3,5,7].

Input: low = 8, high = 10
Output: 1
Explanation: The odd numbers between 8 and 10 are [9].

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

class Solution:
    # Time: O(1)
    # Space: O(1)
    def count_odds(self, low: int, high: int) -> int:
        return (high + 1) // 2 - low // 2

Time	Space
O(1)	O(1)