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