【LeetCode】C++ 3. Longest Substring Without Repeating Characters

陈胖纸

于 2022-03-08 19:32:28 发布

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分类专栏： Leetcode 文章标签：散列表蓝桥杯数据结构

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本文探讨如何使用Python解决字符串中查找最长无重复字符子串的问题，通过实例演示Solution类的方法，包括如何利用unordered_set存储字符状态并更新最长子串长度。理解并应用这个算法有助于提升字符串处理能力。

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Given a string s, find the length of the longest substring without repeating characters.

Example 1:

Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Example 2:

Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        int res=0,left=0,i=0,n=s.length();
        unordered_set<char> t;
        while (i<n){
            if (!t.count(s[i])){
                t.insert(s[i++]);
                res = max(res,int(t.size()));
            }
            else t.erase(s[left++]);
        }
        return res;
    }
};