longestSubstring

#include<iostream>

#include<vector>

#include<algorithm>

#include<string>

using namespace std;

int lengthOfLongestSubsring(string s)

{
const int ascII = 26;
int last[ascII] = { -1 };
int max_len = 0;
int start = 0;
for (int i = 0;i < s.size();++i)
{
if (last[s[i] - 'a'] >= start)
{
max_len = max(max_len, i - start);
start = last[s[i] - 'a'] + 1;
}
last[s[i] - 'a'] = i;
}
return max(int(s.size() - start), max_len);

}

int main()

{
string s("qpxrjxkltzyx");
cout << lengthOfLongestSubsring(s) << endl;

}