Shared via Rust Playground

playground.rs

#![feature(str_char)]

fn to_word(mut n: u32) -> String{
    let mut str = String::new();
    for _ in 0..10{
        let c = match n%5{
            0 => 'A',
            1 => 'B',
            2 => 'C',
            3 => 'D',
            4 => 'E',
            _ => unreachable!()
        };
        n /= 5;
        str = format!("{}{}", c, str);
    }
    return str;
}

fn main(){
    let mut c = 0;
    'next_i: for i in 0..9765625 {
        if i % (9765625 / 100) == 0 {
            println!("{}%", i / (9765625 / 100));
        }
        let str = to_word(i);
        if str.char_at(0) != 'E' && str.char_at(0) != 'A' {continue 'next_i;}
        for l in 0..9{
            if str.char_at(l) == str.char_at(l+1) {continue 'next_i;}
            if str.char_at(l) == 'A' && str.char_at(l+1) == 'E' {continue 'next_i;}
            if str.char_at(l) == 'E' && str.char_at(l+1) == 'A' {continue 'next_i;}
        }
        c += 1;
    }
    println!("{}", c)
}