From d07cb98e07a40de1bd1f23a378611b3f37d4b4a9 Mon Sep 17 00:00:00 2001 From: Ivan Reshetnikov Date: Sun, 10 Nov 2024 21:53:30 +0500 Subject: [PATCH] Add one solution for round 985 --- codeforces/round-985/problem_a/Cargo.lock | 7 ++ codeforces/round-985/problem_a/Cargo.toml | 6 ++ codeforces/round-985/problem_a/README.md | 86 ++++++++++++++++++++++ codeforces/round-985/problem_a/src/main.rs | 59 +++++++++++++++ 4 files changed, 158 insertions(+) create mode 100644 codeforces/round-985/problem_a/Cargo.lock create mode 100644 codeforces/round-985/problem_a/Cargo.toml create mode 100644 codeforces/round-985/problem_a/README.md create mode 100644 codeforces/round-985/problem_a/src/main.rs diff --git a/codeforces/round-985/problem_a/Cargo.lock b/codeforces/round-985/problem_a/Cargo.lock new file mode 100644 index 0000000..0288093 --- /dev/null +++ b/codeforces/round-985/problem_a/Cargo.lock @@ -0,0 +1,7 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +version = 3 + +[[package]] +name = "problem_a" +version = "0.1.0" diff --git a/codeforces/round-985/problem_a/Cargo.toml b/codeforces/round-985/problem_a/Cargo.toml new file mode 100644 index 0000000..ddb6f5a --- /dev/null +++ b/codeforces/round-985/problem_a/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "problem_a" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/codeforces/round-985/problem_a/README.md b/codeforces/round-985/problem_a/README.md new file mode 100644 index 0000000..415ebdb --- /dev/null +++ b/codeforces/round-985/problem_a/README.md @@ -0,0 +1,86 @@ +# A. Set + +[Codeforces](https://codeforces.com/contest/2029/problem/A) + +You are given a positive integer `k` and a set `S` of all integers from `l` to `r` (inclusive). + +You can perform the following two-step operation any number of times (possibly zero): + +First, choose a number `x` from the set `S`, such that there are at least `k` multiples of `x` in `S` +(including `x` itself); + +Then, remove `x` from `S` (note that nothing else is removed). + +Find the maximum possible number of operations that can be performed. + + +## Input + +Each test contains multiple test cases. The first line of the input contains a single integer `t` +(1 ≤ `t` ≤ 104) — the number of test cases. The description of test cases follows. + +The only line of each test case contains three integers `l`, `r`, and `k` (1 ≤ `l` ≤ `r` ≤ 109, 1 ≤ `k` ≤ `r` − `l` + 1) — the minimum integer in `S`, the maximum integer in `S`, and the parameter `k`. + + +## Output + +For each test case, output a single integer — the maximum possible number of operations that can be performed. + + +## Example + +Input + +``` +8 +3 9 2 +4 9 1 +7 9 2 +2 10 2 +154 220 2 +147 294 2 +998 24435 3 +1 1000000000 2 +``` + +Output + +``` +2 +6 +0 +4 +0 +1 +7148 +500000000 +``` + + +## Note + +In the first test case, initially, S={3,4,5,6,7,8,9}. + +One possible optimal sequence of operations is: + +- Choose x=4 for the first operation, since there are two multiples of 4 in S: 4 and 8. S becomes equal to {3,5,6,7,8,9}; +- Choose x=3 for the second operation, since there are three multiples of 3 in S: 3, 6, and 9. S becomes equal to {5,6,7,8,9}. + +In the second test case, initially, S={4,5,6,7,8,9}. One possible optimal sequence of operations is: + +- Choose x=5, S becomes equal to {4,6,7,8,9}; +- Choose x=6, S becomes equal to {4,7,8,9}; +- Choose x=4, S becomes equal to {7,8,9}; +- Choose x=8, S becomes equal to {7,9}; +- Choose x=7, S becomes equal to {9}; +- Choose x=9, S becomes equal to {}. + +In the third test case, initially, S={7,8,9}. For each x in S, no multiple of x other than x itself can be found in S. +Since k=2, you can perform no operations. + +In the fourth test case, initially, S={2,3,4,5,6,7,8,9,10}. One possible optimal sequence of operations is: + +- Choose x=2, S becomes equal to {3,4,5,6,7,8,9,10}; +- Choose x=4, S becomes equal to {3,5,6,7,8,9,10}; +- Choose x=3, S becomes equal to {5,6,7,8,9,10}; +- Choose x=5, S becomes equal to {6,7,8,9,10}. diff --git a/codeforces/round-985/problem_a/src/main.rs b/codeforces/round-985/problem_a/src/main.rs new file mode 100644 index 0000000..54f90a1 --- /dev/null +++ b/codeforces/round-985/problem_a/src/main.rs @@ -0,0 +1,59 @@ +use std::io; + +fn count_max_ops(l: usize, r: usize, k: usize) -> usize { + let n = r / k; + + if n < l { + return 0; + } + + n - l + 1 +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn sample_tests() { + assert_eq!(count_max_ops(3, 9, 2), 2); + assert_eq!(count_max_ops(4, 9, 1), 6); + assert_eq!(count_max_ops(7, 9, 2), 0); + assert_eq!(count_max_ops(2, 10, 2), 4); + assert_eq!(count_max_ops(154, 220, 2), 0); + assert_eq!(count_max_ops(147, 294, 2), 1); + assert_eq!(count_max_ops(998, 24435, 3), 7148); + assert_eq!(count_max_ops(1, 1000000000, 2), 500000000); + } + + #[test] + fn edge_cases() { + assert_eq!(count_max_ops(1, 1, 1), 1); + assert_eq!(count_max_ops(1, 1000000000, 1), 1000000000); + } +} + +fn main() { + let stdin = io::stdin(); + let mut buffer = String::new(); + + stdin.read_line(&mut buffer).unwrap(); + let t: usize = buffer.trim().parse().unwrap(); + + for _i in 0..t { + buffer.clear(); + stdin.read_line(&mut buffer).unwrap(); + let params: Vec = buffer + .trim() + .split_whitespace() + .map(|s| s.parse::().unwrap()) + .collect(); + + let l = params[0]; + let r = params[1]; + let k = params[2]; + + let res = count_max_ops(l, r, k); + println!("{}", res); + } +}