struct Solution; impl Solution { pub fn detect_capital_use(word: String) -> bool { let v: Vec = word.chars().collect(); if v[0].is_lowercase() { return v.iter().all(|&c| c.is_lowercase()); } if v.len() > 1 { let b = v[1].is_lowercase(); return v.iter().skip(1).all(|&c| c.is_lowercase() == b); } true } } fn main() { let word = String::from("USA"); print!("{}", Solution::detect_capital_use(word)); //true }