struct Solution; impl Solution { pub fn unique_occurrences(arr: Vec) -> bool { let (mut counter, mut set) = ([0; 2001], [false; 1000]); arr.iter().for_each(|&x| counter[(x + 1000) as usize] += 1); for &x in counter.iter().filter(|&&x| x > 0) { match set[x as usize] { true => return false, false => set[x as usize] = true } } true } } fn main() { let arr = vec![1,2,2,1,1,3]; print!("{}", Solution::unique_occurrences(arr)); }