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LeetCode solutions

1630. Count Odd Numbers in an Interval Range

My accepted Python solution to LeetCode problem 1630, Count Odd Numbers in an Interval Range, running in 30ms.

  • Difficulty: Easy
  • Python
  • Runtime 30ms
  • Memory 17.2MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 30ms, memory 17.2MB, accepted 2025-12-24.

python
class Solution:
    def countOdds(self, low: int, high: int) -> int:
        # Number of integers from low to high (inclusive)
        count = high - low + 1
        
        # If both low and high are odd, we have (count + 1) // 2 odd numbers
        # If either is odd, we have (count + 1) // 2 odd numbers  
        # If both are even, we have count // 2 odd numbers
        
        # Simplified: if either endpoint is odd, add 1 then divide by 2
        # Otherwise just divide by 2
        
        if low % 2 == 1 or high % 2 == 1:
            return (count + 1) // 2
        return count // 2

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