65 lines
1.1 KiB
Markdown
65 lines
1.1 KiB
Markdown
# Leetcode Count-Odd-Numbers-in-an-Interval-Range
|
||
|
||
#### 2022-07-23 15:09
|
||
|
||
> ##### Algorithms:
|
||
> #algorithm #math
|
||
> ##### Difficulty:
|
||
> #coding_problem #difficulty-easy
|
||
> ##### Additional tags:
|
||
> #leetcode
|
||
> ##### Revisions:
|
||
> N/A
|
||
|
||
##### Related topics:
|
||
```expander
|
||
tag:#math
|
||
```
|
||
|
||
|
||
|
||
##### Links:
|
||
- [Link to problem](https://leetcode.com/problems/count-odd-numbers-in-an-interval-range/)
|
||
___
|
||
### Problem
|
||
|
||
Given two non-negative integers `low` and `high`. Return the _count of odd numbers between_ `low` _and_ `high` _(inclusive)_.
|
||
|
||
#### Examples
|
||
|
||
**Example 1:**
|
||
|
||
**Input:** low = 3, high = 7
|
||
**Output:** 3
|
||
**Explanation:** The odd numbers between 3 and 7 are [3,5,7].
|
||
|
||
**Example 2:**
|
||
|
||
**Input:** low = 8, high = 10
|
||
**Output:** 1
|
||
**Explanation:** The odd numbers between 8 and 10 are [9].
|
||
|
||
#### Constraints
|
||
|
||
- `0 <= low <= high <= 10^9`
|
||
|
||
### Thoughts
|
||
|
||
> [!summary]
|
||
> This is a #math problem.
|
||
|
||
The problem is intended to be solved with math.
|
||
|
||
The key to find the solution is by analyzing and find common
|
||
rules.
|
||
|
||
### Solution
|
||
|
||
```cpp
|
||
class Solution {
|
||
public:
|
||
int countOdds(int low, int high) {
|
||
return ((low % 2) | (high % 2)) + (high - low) / 2;
|
||
}
|
||
};
|
||
``` |