如果一个正整数 $k$ 满足存在唯一的一组正整数三元组 $(a, b, c)$，使得 $a, b, c$ 构成等差数列（按此顺序），且满足 $a^2 + b^2 + k = c^2$，则称 $k$ 为一个 jimp 数。
计算不超过给定整数 $n$ 的 jimp 数的个数。
输入格式
仅一行，包含一个整数 $n$ ($1 \le n \le 10^{11}$)。
输出格式
输出一个整数：问题的答案。
样例
样例输入 1
5
样例输出 1
2
样例输入 2
100
样例输出 2
25
QOJ.ac
QOJ
حد الوقت: 2.0 s
حد الذاكرة: 512 MB
مجموع النقاط: 100
قابلة للهجوم ✓
#12331. Jimp Numbers
الإحصائيات
تم استخدام هذه المسألة في المسابقات التالية:
AI Translation —
This statement was translated using AI and may contain inaccuracies. Please refer to the original statement if in doubt.
Editorials
| ID | Type | Status | Title | Posted By | Last Updated | Actions |
|---|---|---|---|---|---|---|
| #533 | Editorial | Open | 集训队作业 解题报告 by 卢毅奇 | Qingyu | 2026-01-02 21:50:17 | Download |
Discussions
About Discussions
The discussion section is only for posting: General Discussions (problem-solving strategies, alternative approaches), and Off-topic conversations.
This is NOT for reporting issues! If you want to report bugs or errors, please use the Issues section below.
Open Discussions 0
No discussions in this category.
Issues
About Issues
If you find any issues with the problem (statement, scoring, time/memory limits, test cases, etc.), you may submit an issue here. A problem moderator will review your issue.
Guidelines:
- This is not a place to publish discussions, editorials, or requests to debug your code. Issues are only visible to you and problem moderators.
- Do not submit duplicated issues.
- Issues must be filed in English or Chinese only.
Active Issues 0
No issues in this category.
Closed/Resolved Issues 0
No issues in this category.