3. 无重复字符的最长子串

class Solution {
    public int lengthOfLongestSubstring(String s) {
        Map<Character, Integer> map = new HashMap<Character, Integer>();
        int length = 0;

        for (int left = 0, right = 0; right < s.length(); right++) {
            if (map.containsKey(s.charAt(right))) {
                left = Math.max(left, map.get(s.charAt(right)) + 1);
            }

            map.put(s.charAt(right), right);
            length = Math.max(length, right - left + 1);
        }

        return length;
    }
}

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