LeetCode 3 Longest Substring Without Repeating Characters，leetcoderepeating

LeetCode

3 Longest Substring Without Repeating Characters

题目

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3. For “bbbbb” the longest substring is “b”, with the length of 1.

解答

class Solution {
public:
    int lengthOfLongestSubstring(string s) 
    {
        map<char, int> m;
        int maxLen = 0;
        int lastRepeatPos = -1;
        for(int i = 0; i < s.size(); i++)
        {
            if (m.find(s[i]) != m.end() && lastRepeatPos < m[s[i]]) 
                lastRepeatPos = m[s[i]];
            else if ( i - lastRepeatPos > maxLen )
                maxLen = i - lastRepeatPos;
            m[s[i]] = i;
        }
        return maxLen;
    }
};