fn main() {}

fn length_of_longest_substring(s: String) -> i32 {
    if s.is_empty() {
        return 0;
    }

    let mut char_idx_map = [-1_i64; 128];

    let mut left: usize = 0;
    let mut right: usize = 1;

    let mut best = 0;

    let bytes = s.as_bytes();

    while right <= s.len() {
        let last_char = bytes[right - 1];

        let last_seen = char_idx_map[last_char as usize];

        if last_seen >= left as i64 {
            left = (last_seen + 1) as usize;
            right = right.max(left + 1);
        } else {
            best = best.max(right - left);
            char_idx_map[last_char as usize] = right as i64 - 1;
            right += 1;
        }
    }
    best as _
}

#[cfg(test)]
mod tests {
    use super::length_of_longest_substring;

    #[test]
    fn test1() {
        assert_eq!(length_of_longest_substring("abcabcbb".to_string()), 3);
    }
    #[test]
    fn test2() {
        assert_eq!(length_of_longest_substring("bbbbb".to_string()), 1);
    }
    #[test]
    fn test3() {
        assert_eq!(length_of_longest_substring("pwwkew".to_string()), 3);
    }
    #[test]
    fn test4() {
        assert_eq!(length_of_longest_substring("".to_string()), 0);
    }
    #[test]
    fn test5() {
        assert_eq!(length_of_longest_substring("S".to_string()), 1);
    }
}