Submission #8375517

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Source Code Expand

fn main() {
    let s = std::io::stdin();
    let mut sc = Scanner { stdin: s.lock() };
    let n: usize = sc.read();
    let mut t: i64 = sc.read();
    let mut time = Vec::<i64>::new();
    let mut mint: i64 = 0;
    for _ in 0 .. n {
        let (a, b) = (sc.read::<i64>(), sc.read::<i64>());
        mint += b;
        time.push(a - b);
    }
    if mint > t {
        println!("-1");
        return;
    }
    t -= mint;
    time.sort();
    let myself = time.iter().scan(0, |r, &x|
        if *r + x <= t {
            *r += x;
            Some(0)
        } else {
            None
        }).count();
    println!("{}", time.len() - myself);
}

pub struct Scanner<R> {
    stdin: R,
}

impl<R: std::io::Read> Scanner<R> {
    pub fn read<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf = self
            .stdin
            .by_ref()
            .bytes()
            .map(|b| b.unwrap())
            .skip_while(|&b| b == b' ' || b == b'\n')
            .take_while(|&b| b != b' ' && b != b'\n')
            .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