3. 无重复字符的最长子串

题目链接：https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/

java 代码

执行用时：2 ms, 在所有 Java 提交中击败了95.98% 的用户
内存消耗：41.4 MB, 在所有 Java 提交中击败了5.02% 的用户

class Solution {
    public int lengthOfLongestSubstring(String s) {
        if (s.length() == 1) { return 1;}
        int cursor, end = 1, length = s.length();
        int beginAgain = 0, longest = 0;
        while (end < length) {
            cursor = beginAgain;
            while (cursor < end) {
                if (s.charAt(cursor) == s.charAt(end)) {
                    beginAgain = cursor + 1;
                    break;
                }
                cursor++;
            }
            longest = Math.max(longest, end - beginAgain + 1);
            end++;
        }
        return longest;
    }
}

swift 代码

class Solution {
    func lengthOfLongestSubstring(_ s: String) -> Int {
        if s.isEmpty { return 0}
        let length = s.count
        var count = 0
        var str = Array(s)
        var cursor = 0, end = 0, beginAgain = 0
        while end < length {
            cursor = beginAgain
            while cursor < end {
                if str[cursor] == str[end] {
                    beginAgain = cursor + 1
                    break
                }
                cursor += 1
            }
            count = max(count, end - beginAgain + 1)
            end += 1
        }
        return count
    }
}