题解 | #字符统计#

• 解法一：
  Vec

use std::io;
fn main() {
    let mut s = String::new();
    io::stdin().read_line(&mut s).expect("Failed to read line");
    let mut v = Vec::new();
    for i in 48..58u8 {
        v.push((i,0u16));
    }
    for i in 97..123u8 {
        v.push((i,0u16));
    }
    for i in s.into_bytes() {
        match i {
            97..=122 => v[i as usize - 87].1 += 1,
            48..=57 => v[i as usize - 48].1 += 1,
            _ => {}
        }
    }
    v.sort_by(|a,b|b.1.cmp(&(a.1)));
    for (u,num) in v.iter() {
        if *num != 0 {
            print!("{}",char::from(*u));
        }else{
            break;
        }
    }
}

解法二：HashMap：

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