3. Longest Substring Without Repeating Characters Medium

1/**
2 * [3] Longest Substring Without Repeating Characters
3 *
4 * Given a string s, find the length of the longest substring without repeating characters.
5 * 
6 * Example 1:
7 * 
8 * Input: s = "abcabcbb"
9 * Output: 3
10 * Explanation: The answer is "abc", with the length of 3.
11 * 
12 * Example 2:
13 * 
14 * Input: s = "bbbbb"
15 * Output: 1
16 * Explanation: The answer is "b", with the length of 1.
17 * 
18 * Example 3:
19 * 
20 * Input: s = "pwwkew"
21 * Output: 3
22 * Explanation: The answer is "wke", with the length of 3.
23 * Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
24 * 
25 * Example 4:
26 * 
27 * Input: s = ""
28 * Output: 0
29 * 
30 * 
31 * Constraints:
32 * 
33 * 0 <= s.length <= 5 * 10^4
34 * s consists of English letters, digits, symbols and spaces.
35 * 
36 */
37pub struct Solution {}
38
39// problem: https://leetcode.com/problems/longest-substring-without-repeating-characters/
40// discuss: https://leetcode.com/problems/longest-substring-without-repeating-characters/discuss/?currentPage=1&orderBy=most_votes&query=
41
42// submission codes start here
43
44impl Solution {
45    pub fn length_of_longest_substring(s: String) -> i32 {
46        let seq: Vec<char> = s.chars().collect();
47        let len = seq.len();
48        let (mut start, mut end, mut max) = (0, 0, 0);
49
50        while end < len {
51            for idx in start..end {
52                if seq[end] == seq[idx] {
53                    start = idx + 1;
54                    break;
55                }
56            }
57            let curr = end - start + 1;
58            if curr > max {
59                max = curr
60            }
61            end += 1
62        }
63        max as i32
64    }
65}
66
67// submission codes end
68
69#[cfg(test)]
70mod tests {
71    // use super::*;
72
73    #[test]
74    fn test_3() {
75    }
76}
77