题解 | #最长不含重复字符的子字符串#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param s string字符串 
     * @return int整型
     */
    public int lengthOfLongestSubstring (String s) {
        // write code here
        HashMap<Character, Integer> charSet = new HashMap<>();
        int result = 0;
        for(int left = 0, right = 0; right < s.length(); right ++){
            if(charSet.containsKey(s.charAt(right))) charSet.put(s.charAt(right), charSet.get(s.charAt(right)) + 1);
            else charSet.put(s.charAt(right), 1);
            while(charSet.get(s.charAt(right)) > 1) charSet.put(s.charAt(left), charSet.get(s.charAt(left ++)) - 1);
            result = Math.max(result, right - left + 1);
        }
        return result;
    }
}