Peli

use std::io::{stdin, BufRead, BufReader};

fn main() {
    let mut stdin = BufReader::new(stdin());
    let mut cur_line = String::new();

    stdin.read_line(&mut cur_line).unwrap();
    let mut nums = cur_line
    .split_whitespace()
    .map(|s| s.parse::<usize>().unwrap());

    let n = nums.next().unwrap();
    let k = nums.next().unwrap();

    cur_line.clear();
    stdin.read_line(&mut cur_line).unwrap();

    let v = cur_line.as_bytes();

    let mut max_a = 0;
    let mut max_b = 0;
    let mut max_c = 0;

    let mut x = 0;
    let mut ck = 0;

    for i in 0..n {
        ck = (ck + 1).min(k);
        match v[i] {
            b'A' => max_a += 1,
            b'B' => max_b += 1,
            b'C' => max_c += 1,
            _ => (),
        }

        if max_a > 0 && max_b > 0 && max_c > 0 && ck >= 3 {
            x += 1;
            max_a -= 1;
            max_b -= 1;
            max_c -= 1;
            ck -= 3;
        }

        max_a = max_a.min(ck);
        max_b = max_b.min(ck);
        max_c = max_c.min(ck);
    }

    println!("{}", x);
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: WRONG ANSWER

Test 3

Group: 3

Verdict: WRONG ANSWER

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED