Submission #18834984

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Source Code Expand

use std::cmp::min;

fn main() {
    let (r, w) = (std::io::stdin(), std::io::stdout());
    let mut sc = IO::new(r.lock(), w.lock());

    let a = sc.chars();
    let b = sc.chars();
    let mut da = vec![];
    let mut db = vec![];
    let n = a.len();
    for i in 0..n {
        if a[i] != b[i] {
            da.push(a[i]);
            db.push(b[i]);
        }
    }

    if da.len() > 6 {
        println!("NO");
        return;
    }

    if let Some(ans) = min_swaps(&mut da, &mut db, 0) {
        if ans == 1 || ans == 3 {
            println!("YES");
            return;
        }

        let mut a = a.clone();
        a.sort();
        a.dedup();
        if a.len() < n {
            println!("YES");
        } else {
            println!("NO");
        }
    } else {
        println!("NO");
    }
}

fn min_swaps(da: &mut [char], db: &[char], depth: usize) -> Option<usize> {
    if da == db {
        return Some(depth);
    }
    if depth == 3 {
        return None;
    }
    let n = da.len();
    let mut result = 5;
    for i in 0..n {
        for j in 0..i {
            da.swap(i, j);

            if let Some(d) = min_swaps(da, db, depth + 1) {
                result = min(result, d);
            }

            da.swap(i, j);
        }
    }

    if result > 3 {
        None
    } else {
        Some(result)
    }
}

pub struct IO<R, W: std::io::Write>(R, std::io::BufWriter<W>);

impl<R: std::io::Read, W: std::io::Write> IO<R, W> {
    pub fn new(r: R, w: W) -> Self {
        Self(r, std::io::BufWriter::new(w))
    }
    pub fn write<S: ToString>(&mut self, s: S) {
        use std::io::Write;
        self.1.write_all(s.to_string().as_bytes()).unwrap();
    }
    pub fn read<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf = self
            .0
            .by_ref()
            .bytes()
            .map(|b| b.unwrap())
            .skip_while(|&b| b == b' ' || b == b'\n' || b == b'\r' || b == b'\t')
            .take_while(|&b| b != b' ' && b != b'\n' && b != b'\r' && b != b'\t')
            .collect::<Vec<_>>();
        unsafe { std::str::from_utf8_unchecked(&buf) }
            .parse()
            .ok()
            .expect("Parse error.")
    }
    pub fn vec<T: std::str::FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.read()).collect()
    }
    pub fn chars(&mut self) -> Vec<char> {
        self.read::<String>().chars().collect()
    }
}

Submission Info

Judge Result