update: 添加问题“2894.分类求和并作差”的代码和题解(#959)

LetMeFly666 · web-flow · commit 594749efe028 · 2025-05-27T22:15:45.000+08:00
* 2894: WA.cpp (#958) Signed-off-by: LetMeFly666 <814114971@qq.com> * 2894: AC.(cpp+py) + WA.java (#958) cpp - AC,100.00%,19.79% py - AC,100.00%,88.02% Signed-off-by: LetMeFly666 <814114971@qq.com> * 2894: AC.(java+go) (#958) java - AC,100.00%,80.77% go - AC,100.00%,68.18% Signed-off-by: LetMeFly666 <814114971@qq.com> * update: 添加问题“2894.分类求和并作差”的代码和题解(#959) Signed-off-by: LetMeFly666 <814114971@qq.com> * typo: nums2 -> num2 Signed-off-by: LetMeFly666 <814114971@qq.com> --------- Signed-off-by: LetMeFly666 <814114971@qq.com>
diff --git a/Codes/2894-divisible-and-non-divisible-sums-difference.cpp b/Codes/2894-divisible-and-non-divisible-sums-difference.cpp
@@ -0,0 +1,16 @@
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:53:29
+ */
+#if defined(_WIN32) || defined(__APPLE__)
+#include "_[1,2]toVector.h"
+#endif
+
+class Solution {
+public:
+    int differenceOfSums(int n, int m) {
+        return (1 + n) * n / 2 - (m + n / m * m) * (n / m);
+    }
+};
diff --git a/Codes/2894-divisible-and-non-divisible-sums-difference.go b/Codes/2894-divisible-and-non-divisible-sums-difference.go
@@ -0,0 +1,11 @@
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:58:33
+ */
+package main
+
+func differenceOfSums(n int, m int) int {
+    return (1 + n) * n / 2 - (m + n / m * m) * (n / m)
+}
diff --git a/Codes/2894-divisible-and-non-divisible-sums-difference.java b/Codes/2894-divisible-and-non-divisible-sums-difference.java
@@ -0,0 +1,11 @@
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:57:48
+ */
+class Solution {
+    public int differenceOfSums(int n, int m) {
+        return (1 + n) * n / 2 - (m + n / m * m) * (n / m);
+    }
+}
diff --git a/Codes/2894-divisible-and-non-divisible-sums-difference.py b/Codes/2894-divisible-and-non-divisible-sums-difference.py
@@ -0,0 +1,9 @@
+'''
+Author: LetMeFly
+Date: 2025-05-27 21:42:21
+LastEditors: LetMeFly.xyz
+LastEditTime: 2025-05-27 21:54:46
+'''
+class Solution:
+    def differenceOfSums(self, n: int, m: int) -> int:
+        return (1 + n) * n // 2 - (m + n // m * m) * (n // m)
diff --git a/README.md b/README.md
@@ -869,6 +869,7 @@
 |2859.计算K置位下标对应元素的和|简单|<a href="https://leetcode.cn/problems/sum-of-values-at-indices-with-k-set-bits/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/01/25/LeetCode%202859.%E8%AE%A1%E7%AE%97K%E7%BD%AE%E4%BD%8D%E4%B8%8B%E6%A0%87%E5%AF%B9%E5%BA%94%E5%85%83%E7%B4%A0%E7%9A%84%E5%92%8C/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/135836080" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/sum-of-values-at-indices-with-k-set-bits/solutions/2618937/letmefly-2859ji-suan-k-zhi-wei-xia-biao-usyx1/" target="_blank">LeetCode题解</a>|
 |2860.让所有学生保持开心的分组方法数|中等|<a href="https://leetcode.cn/problems/happy-students/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/09/04/LeetCode%202860.%E8%AE%A9%E6%89%80%E6%9C%89%E5%AD%A6%E7%94%9F%E4%BF%9D%E6%8C%81%E5%BC%80%E5%BF%83%E7%9A%84%E5%88%86%E7%BB%84%E6%96%B9%E6%B3%95%E6%95%B0/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/141905408" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/happy-students/solutions/2905023/letmefly-2860rang-suo-you-xue-sheng-bao-t8u1o/" target="_blank">LeetCode题解</a>|
 |2864.最大二进制奇数|简单|<a href="https://leetcode.cn/problems/maximum-odd-binary-number/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/03/13/LeetCode%202864.%E6%9C%80%E5%A4%A7%E4%BA%8C%E8%BF%9B%E5%88%B6%E5%A5%87%E6%95%B0/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/136669293" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/maximum-odd-binary-number/solutions/2683729/letmefly-2864zui-da-er-jin-zhi-qi-shu-ta-30tq/" target="_blank">LeetCode题解</a>|
+|2894.分类求和并作差|简单|<a href="https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2025/05/27/LeetCode%202894.%E5%88%86%E7%B1%BB%E6%B1%82%E5%92%8C%E5%B9%B6%E4%BD%9C%E5%B7%AE/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/148266123" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/solutions/3687620/letmefly-2894fen-lei-qiu-he-bing-zuo-cha-suyc/" target="_blank">LeetCode题解</a>|
 |2900.最长相邻不相等子序列I|简单|<a href="https://leetcode.cn/problems/longest-unequal-adjacent-groups-subsequence-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2025/05/15/LeetCode%202900.%E6%9C%80%E9%95%BF%E7%9B%B8%E9%82%BB%E4%B8%8D%E7%9B%B8%E7%AD%89%E5%AD%90%E5%BA%8F%E5%88%97I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/147990003" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/longest-unequal-adjacent-groups-subsequence-i/solutions/3677963/letmefly-2900zui-chang-xiang-lin-bu-xian-69ua/" target="_blank">LeetCode题解</a>|
 |2903.找出满足差值条件的下标I|简单|<a href="https://leetcode.cn/problems/find-indices-with-index-and-value-difference-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/05/25/LeetCode%202903.%E6%89%BE%E5%87%BA%E6%BB%A1%E8%B6%B3%E5%B7%AE%E5%80%BC%E6%9D%A1%E4%BB%B6%E7%9A%84%E4%B8%8B%E6%A0%87I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/139195914" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/find-indices-with-index-and-value-difference-i/solutions/2789520/letmefly-2903zhao-chu-man-zu-chai-zhi-ti-m92q/" target="_blank">LeetCode题解</a>|
 |2908.元素和最小的山形三元组I|简单|<a href="https://leetcode.cn/problems/minimum-sum-of-mountain-triplets-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/03/29/LeetCode%202908.%E5%85%83%E7%B4%A0%E5%92%8C%E6%9C%80%E5%B0%8F%E7%9A%84%E5%B1%B1%E5%BD%A2%E4%B8%89%E5%85%83%E7%BB%84I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/137151595" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/minimum-sum-of-mountain-triplets-i/solutions/2714346/letmefly-2908yuan-su-he-zui-xiao-de-shan-h3s9/" target="_blank">LeetCode题解</a>|
diff --git a/Solutions/LeetCode 2894.分类求和并作差.md b/Solutions/LeetCode 2894.分类求和并作差.md
@@ -0,0 +1,144 @@
+---
+title: 2894.分类求和并作差：数学O(1)一行解决
+date: 2025-05-27 22:01:09
+tags: [题解, LeetCode, 简单, 数学]
+categories: [题解, LeetCode]
+---
+
+# 【LetMeFly】2894.分类求和并作差：数学O(1)一行解决
+
+力扣题目链接：[https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/](https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/)
+
+<p>给你两个正整数 <code>n</code> 和 <code>m</code> 。</p>
+
+<p>现定义两个整数 <code>num1</code> 和 <code>num2</code> ，如下所示：</p>
+
+<ul>
+	<li><code>num1</code>：范围 <code>[1, n]</code> 内所有 <strong>无法被 </strong><code>m</code><strong> 整除</strong> 的整数之和。</li>
+	<li><code>num2</code>：范围 <code>[1, n]</code> 内所有 <strong>能够被 </strong><code>m</code><strong> 整除</strong> 的整数之和。</li>
+</ul>
+
+<p>返回整数 <code>num1 - num2</code> 。</p>
+
+<p>&nbsp;</p>
+
+<p><strong class="example">示例 1：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 10, m = 3
+<strong>输出：</strong>19
+<strong>解释：</strong>在这个示例中：
+- 范围 [1, 10] 内无法被 3 整除的整数为 [1,2,4,5,7,8,10] ，num1 = 这些整数之和 = 37 。
+- 范围 [1, 10] 内能够被 3 整除的整数为 [3,6,9] ，num2 = 这些整数之和 = 18 。
+返回 37 - 18 = 19 作为答案。
+</pre>
+
+<p><strong class="example">示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 5, m = 6
+<strong>输出：</strong>15
+<strong>解释：</strong>在这个示例中：
+- 范围 [1, 5] 内无法被 6 整除的整数为 [1,2,3,4,5] ，num1 = 这些整数之和 =  15 。
+- 范围 [1, 5] 内能够被 6 整除的整数为 [] ，num2 = 这些整数之和 = 0 。
+返回 15 - 0 = 15 作为答案。
+</pre>
+
+<p><strong class="example">示例 3：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 5, m = 1
+<strong>输出：</strong>-15
+<strong>解释：</strong>在这个示例中：
+- 范围 [1, 5] 内无法被 1 整除的整数为 [] ，num1 = 这些整数之和 = 0 。 
+- 范围 [1, 5] 内能够被 1 整除的整数为 [1,2,3,4,5] ，num2 = 这些整数之和 = 15 。
+返回 0 - 15 = -15 作为答案。
+</pre>
+
+<p>&nbsp;</p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n, m &lt;= 1000</code></li>
+</ul>
+
+
+    
+## 解题方法：数学
+
+这就需要拿出我们小学二年级就学过的**等差数列求和公式** $\lfloor\frac{(首项+尾项)\times 项数}{2}\rfloor$
+
+另外有$num1-num2=(num1+num2)-num2$，而$num1+num2$就是整个数列$1$到$n$的和，$num2$就是首项为$m$尾项为$\lfloor\frac{n}m\rfloor\times m$项数为$\lfloor\frac{n}m\rfloor$的等差数列。
+
++ 时间复杂度$O(1)$
++ 空间复杂度$O(1)$
+
+### AC代码
+
+#### C++
+
+```cpp
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:53:29
+ */
+class Solution {
+public:
+    int differenceOfSums(int n, int m) {
+        return (1 + n) * n / 2 - (m + n / m * m) * (n / m);
+    }
+};
+```
+
+#### Python
+
+```python
+'''
+Author: LetMeFly
+Date: 2025-05-27 21:42:21
+LastEditors: LetMeFly.xyz
+LastEditTime: 2025-05-27 21:54:46
+'''
+class Solution:
+    def differenceOfSums(self, n: int, m: int) -> int:
+        return (1 + n) * n // 2 - (m + n // m * m) * (n // m)
+```
+
+#### Java
+
+```java
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:57:48
+ */
+class Solution {
+    public int differenceOfSums(int n, int m) {
+        return (1 + n) * n / 2 - (m + n / m * m) * (n / m);
+    }
+}
+```
+
+#### Go
+
+```go
+/*
+ * @Author: LetMeFly
+ * @Date: 2025-05-27 21:42:21
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2025-05-27 21:58:33
+ */
+package main
+
+func differenceOfSums(n int, m int) int {
+    return (1 + n) * n / 2 - (m + n / m * m) * (n / m)
+}
+```
+
+> 同步发文于[CSDN](https://letmefly.blog.csdn.net/article/details/148266123)和我的[个人博客](https://blog.letmefly.xyz/)，原创不易，转载经作者同意后请附上[原文链接](https://blog.letmefly.xyz/2025/05/27/LeetCode%202894.%E5%88%86%E7%B1%BB%E6%B1%82%E5%92%8C%E5%B9%B6%E4%BD%9C%E5%B7%AE/)哦~
+>
+> 千篇源码题解[已开源](https://github.com/LetMeFly666/LeetCode)
diff --git a/WhatCanISay.md b/WhatCanISay.md
diff --git a/tryGoPy/BUG!/powershell/toSay.md b/tryGoPy/BUG!/powershell/toSay.md
