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.
1 class Solution { 2 public: 3 int lengthOfLongestSubstring(string s) { 4 int i = 0, j = 0; 5 map<char, int> mp; //值映射的是字符所在的下标位置 6 int len = s.length(); //字符串的长度 7 vector<int> dp(len, 0); //dp[j]表示以第j个字符结尾的不重复子串的长度 8 int maxn = 0; 9 for (j = 0; j < len; j++) { 10 //如果当前的字符已经之前出现过了，并且是在i之后位置的，那么要更新窗口左边的下标 11 if (mp.count(s[j]) > 0) { 12 i = max(i, mp[s[j]] + 1); 13 } 14 dp[j] = j - i + 1; //窗口大小即为以第j个字符结尾的最长不重复子串的长度 15 mp[s[j]] = j; 16 maxn = max(maxn, dp[j]); 17 } 18 return maxn; 19 } 20 };