Kertoma

use std::f32::consts::{E, PI};
use std::io::{BufRead, BufReader};

fn main() {
    let mut input = BufReader::new(std::io::stdin());
    let mut size = String::new();
    input.read_line(&mut size).unwrap();
    let split = size.split_whitespace();

    let mut digits = 0.0;
    let mut nums: Vec<f32> = Vec::with_capacity(9);

    for c in split {
        let num = c.parse::<f32>().unwrap();

        digits += num;
        nums.push(num);
    }

    for i in 1..90001 {
        //
        let d = cnt_digits(i as f32);
        if d == digits {
            return println!("{}", i);
        }

        if d == digits + 1.0 {
            break;
        }
    }
}

fn cnt_digits(n: f32) -> f32 {
    f32::floor(n * (n / E).log10() + (2.0 * PI * n).log10() / 2.0) + 1.0
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: WRONG ANSWER