Longest_Sub_String_without_Repeat_Characters_Dictionary

Longest_Sub_String_without_Repeat_Characters_Dictionary.cpp

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        vector<int> dict(256,-1);     
        int maxLength = 0, start = -1;
        for(int i =0; i<s.size(); i++)
        {
            if(dict[s[i]] > start)
                start = dict[s[i]];
            dict[s[i]] = i;
            maxLength = max(maxLength, i - start);
        }      
        return maxLength;
    }
};