题目

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

Example 1:

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

Example 2:

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

Example 3:

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

思路分析

又是一道大水题，三重循环无脑解，一点睡觉美滋滋。

我的代码

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        int len = 0;
        for (int i = 0; i < s.length(); i++) {
            int start = i, end = i;
            for (int j = i + 1; j < s.length(); j++) {
                int flag = 1;
                for (int k = i; k < j; k++) {
                    if (s[k] == s[j]) {
                        flag = 0;
                        break;
                    }
                }
                if (flag) {
                    end = j;
                }
                else {
                    break;
                }
            }
            if (end - start + 1 > len) {
                len = end - start + 1;
            }
        }
        return len;
    }
};