P6210 "SWTR-4" Easy Math Problems
Background
The math teacher assigned Little A $2$ Easy Math Problems.
Description
Given $n,c,f,l,r$, define the set $S=\{x\in\mathbb{N_+}\mid\gcd(x,n)\leq c\}$ and the set $Q=\{x\in S\mid l\leq x\leq r\}$.
- Set $S$ contains all positive integers whose $\gcd$ with $n$ is at most $c$, and set $Q$ contains the elements in $S$ that are not less than $l$ and not greater than $r$.
Question 1: Find the $f$-th smallest number in set $S$.
Question 2: Find the number of elements in set $Q$.
Since the numbers are very large, Little A wants you to help compute the answers.
Input Format
A single line with five integers $n,c,f,l,r$ — with meanings as described in the statement.
Output Format
Output two lines of integers — the first line is the answer to Question 1, and the second line is the answer to Question 2.
Explanation/Hint
[Sample $1$ Explanation]
$S=\{1,2,3,5,7,9,10,11,13,14,15,17,\dots\},Q=\{10,11,13,14,15,17\}$. It can be seen that the $8$-th smallest number in $S$ is $11$, and the number of elements in $Q$ is $6$.
[Constraints and Notes]
**This problem uses bundled tests.**
Subtask $1(15\%)$: $n\leq 10^3$, $r\leq 10^3$, $f\leq 10^3$.
Subtask $2(35\%)$: $n\leq 10^5$, $r\leq 10^5$, $f\leq 10^5$.
Subtask $3(35\%)$: $n\leq 10^6$, $r\leq 10^{12}$, $f\leq 10^{12}$.
Subtask $4(15\%)$: $n\leq 10^7$, $r\leq 10^{10^5}$, $f\leq 10^{10^5}$.
For $100\%$ of the testdata, $1\leq c\leq n\leq 10^7$, $1\leq l\leq r\leq 10^{10^5}$, $1\leq f\leq 10^{10^5}$.
[Tips]
Want to solve this problem with $n\log n$?
[Time Limit]
For the first $3$ subtasks, the time limit is $1\rm{s}$, and for the remaining subtask it is $500\rm{ms}$.
[Source]
[Sweet Round 04](https://www.luogu.com.cn/contest/26414)$\ \ $B
idea & std: [Alex_Wei](https://www.luogu.com.cn/user/123294), verification: [xtx1092515503](https://www.luogu.com.cn/user/123369) & [FrenkiedeJong21](https://www.luogu.com.cn/user/203968) & [chenxia25](https://www.luogu.com.cn/user/138400)
Translated by ChatGPT 5