n0003_longest_substring.rs

/**
 * [3] Longest Substring Without Repeating Characters
 *
 * Given a string, find the length of the longest substring without repeating characters.
 *
 * Example:
 *
 * Input: "abcabcbb"
 * Output: 3
 * Explanation: The answer is "abc", with the length of 3.
 *
 */
pub struct Solution {}

// submission codes start here

impl Solution {
    pub fn length_of_longest_substring(s: String) -> i32 {
        let seq: Vec<char> = s.chars().collect();
        let len = seq.len();
        let (mut start, mut end, mut max) = (0, 0, 0);

        while end < len {
            for idx in start..end {
                if seq[end] == seq[idx] {
                    start = idx + 1;
                    break
                }
            }
            let curr = end - start + 1;
            if curr > max { max = curr }
            end += 1
        }
        max as i32
    }
}

// submission codes end

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

    #[test]
    fn test_3() {
        assert_eq!(Solution::length_of_longest_substring("abcabcbb".to_string()), 3);
        assert_eq!(Solution::length_of_longest_substring("bbbb".to_string()), 1);
        assert_eq!(Solution::length_of_longest_substring("pwwkew".to_string()), 3);
    }
}