AtCoder Beginner Contest 036 C - 座圧

,

http://abc036.contest.atcoder.jp/tasks/abc036_c

座標圧縮単体の問題。

solution

やる。 要素を昇順に並べ重複除去した結果内の順位で置換。

implementation

for loopで渡ってくるのが何なのかよく分からない。 &なしだとpointerっぽいけど、どうして2重化したのか。

// #[macro_use] extern crate text_io; {{{
// https://crates.io/crates/text_io/0.1.3, Oliver Schneider, MIT License
macro_rules! read( () => { read!("{}") }; ($text:expr) => {{ let value; scan!($text, value); value }}; ($text:expr, $input:expr) => {{ let value; scan!($input => $text, value); value }}; );
macro_rules! scan( ($text:expr, $($arg:ident),*) => { scan!(std::io::stdin().bytes().map(|c| c.unwrap()) => $text, $($arg),*) }; ($input:expr => $text:expr, $($arg:ident),*) => {{ use std::io::Read; use std::str::FromStr; /* typesafe macros :) */ let text: &'static str = $text; let stdin: &mut Iterator<Item = u8> = &mut ($input); let mut text = text.bytes(); $( loop { match text.next() { Some(b'{') => match text.next() { Some(b'{') => assert_eq!(Some(b'{'), stdin.next()), Some(b'}') => { let s: Vec<u8> = match text.next() { Some(c) => stdin.take_while(|&ch| ch != c).collect(), None => stdin.take_while(|ch| !b"\t\r\n ".contains(ch)).collect(), }; let s = match std::str::from_utf8(&s) { Ok(s) => s, Err(e) => { let n = e.valid_up_to(); if n == 0 { panic!("input was not valid utf8: {:?}", s); } else { panic!("input was only partially valid utf8: \"{}\" followed by {:?}", std::str::from_utf8(&s[..n]).unwrap(), &s[n..]); } } }; $arg = FromStr::from_str(s).expect(&format!("could not parse {} as target type of {}", s, stringify!($arg))); break; } Some(_) => panic!("found bad curly brace"), None => panic!("found single open curly brace at the end of the format string"), }, Some(c) => assert_eq!(Some(c), stdin.next()), None => panic!("Bad read! format string: did not contain {{}}"), } })* for c in text { assert_eq!(Some(c), stdin.next()); } }}; );
// ' }}}
use std::collections::BTreeSet;
use std::collections::HashMap;

fn main() {
    let n: usize = read!();
    let mut a: Vec<i64> = Vec::with_capacity(n);
    for _ in 0..n {
        a.push(read!());
    }
    let mut s = BTreeSet::new();
    for it in &a {
        s.insert(it);
    }
    let mut f: HashMap<i64,usize> = HashMap::new();
    for (i, it) in s.iter().enumerate() {
        f.insert(**it, i);
    }
    for it in &a {
        println!("{}", f.get(it).unwrap());
    }
}