【Hot100】LeetCode—3. 无重复字符的最长子串

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• 原题链接：3. 无重复字符的最长子串

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1- 思路

滑动窗口

• 借助 HashSet 来实现判重
• 通过指针 i 和 right 指针实现一个滑动窗口

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2- 实现

⭐3. 无重复字符的最长子串——题解思路

class Solution {public int lengthOfLongestSubstring(String s) {HashSet<Character> hs = new HashSet<>();int res = 0;int right = 0;for(int i = 0 ; i < s.length();i++){// 移除前一个if (i != 0) {hs.remove(s.charAt(i - 1));}while (right < s.length() && !hs.contains(s.charAt(right))) {hs.add(s.charAt(right));right++;}res = Math.max(res, hs.size());}return res;}
}

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3- ACM 实现

public class noDuplicate {private static int nonDuplicate(String s){HashSet<Character> hs = new HashSet<>();int res = 0;int right = 0;// 2.遍历for(int i = 0 ; i < s.length();i++){// 2.2 去重if(i>0){hs.remove(s.charAt(i-1));}// 2.3 whilewhile(right<s.length() && !hs.contains(s.charAt(right))){hs.add(s.charAt(right));right++;}res = Math.max(res,hs.size());}return res;}public static void main(String[] args) {Scanner sc = new Scanner(System.in);System.out.println("输入字符串");String s = sc.nextLine();System.out.println("结果是"+nonDuplicate(s));}
}

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