From 5c66df3c0ff4aebba8cb225e6ac600c9dfc0f7d3 Mon Sep 17 00:00:00 2001
From: juan <juancloudcomputing@protonmail.com>
Date: Sat, 23 Jul 2022 15:28:38 +0800
Subject: [PATCH] vault backup: 2022-07-23 15:28:38

---
 ...xcluding-the-Minimum-and-Maximum-Salary.md | 76 +++++++++++++++++++
 ... Count-Odd-Numbers-in-an-Interval-Range.md | 36 ++++++++-
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 create mode 100644 OJ notes/pages/Leetcode Average-Salary-Excluding-the-Minimum-and-Maximum-Salary.md

diff --git a/OJ notes/pages/Leetcode Average-Salary-Excluding-the-Minimum-and-Maximum-Salary.md b/OJ notes/pages/Leetcode Average-Salary-Excluding-the-Minimum-and-Maximum-Salary.md
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+# Leetcode Average-Salary-Excluding-the-Minimum-and-Maximum-Salary
+
+#### 2022-07-23 15:27
+
+> ##### Difficulty:
+> #coding_problem #difficulty-easy
+> ##### Additional tags:
+> #leetcode #math
+> ##### Revisions:
+> N/A
+
+##### Related topics:
+```expander
+tag:#math
+```
+ 
+ 
+
+##### Links:
+- [Link to problem](https://leetcode.com/problems/average-salary-excluding-the-minimum-and-maximum-salary/)
+___
+### Problem
+
+You are given an array of **unique** integers `salary` where `salary[i]` is the salary of the `ith` employee.
+
+Return _the average salary of employees excluding the minimum and maximum salary_. Answers within `10-5` of the actual answer will be accepted.
+
+#### Examples
+
+**Example 1:**
+
+**Input:** salary = [4000,3000,1000,2000]
+**Output:** 2500.00000
+**Explanation:** Minimum salary and maximum salary are 1000 and 4000 respectively.
+Average salary excluding minimum and maximum salary is (2000+3000) / 2 = 2500
+
+**Example 2:**
+
+**Input:** salary = [1000,2000,3000]
+**Output:** 2000.00000
+**Explanation:** Minimum salary and maximum salary are 1000 and 3000 respectively.
+Average salary excluding minimum and maximum salary is (2000) / 1 = 2000
+
+#### Constraints
+
+-   `3 <= salary.length <= 100`
+-   `1000 <= salary[i] <= 106`
+-   All the integers of `salary` are **unique**.
+
+### Thoughts
+
+> [!summary]
+> This is a #math problem
+
+The one solution I came up with is using math.
+
+When counting total, be warned of integer overflows.
+
+### Solution
+
+```cpp
+class Solution {
+public:
+  double average(vector<int> &salary) {
+    double ans = 0, factor = salary.size() - 2;
+    int maxSal = 0, minSal = 1000001;
+
+    for (int i = 0, size = factor + 2; i < size; i++) {
+      ans += salary[i] / factor;
+      maxSal = max(maxSal, salary[i]);
+      minSal = min(minSal, salary[i]);
+    }
+    return ans - minSal / factor - maxSal / factor;
+  }
+};
+```
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diff --git a/OJ notes/pages/Leetcode Count-Odd-Numbers-in-an-Interval-Range.md b/OJ notes/pages/Leetcode Count-Odd-Numbers-in-an-Interval-Range.md
index 27fffa1..22efae6 100644
--- a/OJ notes/pages/Leetcode Count-Odd-Numbers-in-an-Interval-Range.md	
+++ b/OJ notes/pages/Leetcode Count-Odd-Numbers-in-an-Interval-Range.md	
@@ -13,23 +13,53 @@
 
 ##### Related topics:
 ```expander
-tag:#<INSERT_TAG_HERE>
+tag:#math
 ```
  
  
 
 ##### Links:
-- [Link to problem]()
+- [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 #template_remove_me
+> 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;
+  }
+};
+```
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