[LeetCode] 3. Longest Substring Without Repeating Characters about leetcode

rust解法:

use std::cmp::max;
use std::collections::HashMap;

pub struct Solution {}

impl Solution {
    pub fn longest_substring_without_repeating_characters1(s: &str) -> usize {
        let mut res: usize = 0;
        let mut left: i32 = -1;
        let mut m = HashMap::new();
        for (k, v) in s.chars().enumerate() {
            if m.contains_key(&v) && *m.get(&v).unwrap() as i32 > left {
                left = *m.get(&v).unwrap() as i32;
            }
            m.insert(v, k);
            res = max(res, (k as i32 - left) as usize);
        }
        res
    }

    pub fn longest_substring_without_repeating_characters2(s: &str) -> usize {
        let mut m = [-1; 128];
        let mut res: usize = 0;
        let mut left: i32 = -1;
        for (k, v) in s.chars().enumerate() {
            left = max(left, m[v as usize]);
            m[v as usize] = k as i32;
            res = max(res, (k as i32 - left) as usize);
        }
        res
    }
}

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

    #[test]
    fn longest_substring_without_repeating_characters() {
        let s1 = "abcabcbb";
        assert_eq!(
            3,
            Solution::longest_substring_without_repeating_characters1(s1)
        );
        assert_eq!(
            3,
            Solution::longest_substring_without_repeating_characters2(s1)
        );

        let s2 = "bbbbb";
        assert_eq!(
            1,
            Solution::longest_substring_without_repeating_characters1(s2)
        );
        assert_eq!(
            1,
            Solution::longest_substring_without_repeating_characters2(s2)
        );

        let s3 = "pwwkew";
        assert_eq!(
            3,
            Solution::longest_substring_without_repeating_characters1(s3)
        );
        assert_eq!(
            3,
            Solution::longest_substring_without_repeating_characters2(s3)
        );
    }
}