Longest Substring Without Repeat

#include <iostream>

#include <string>

using namespace std;

class LongSubstring {

public:

       LongSubstring();

       ~LongSubstring();

       int getLongestSubstring(string s);

       string out;

       int maxlength;

private:

       bool isMax(int a, int b);

       void map_to_hash(char, int);

       int get_hash_value(char);

       void update(int, int);

       int start;

       int hash[26];

};

bool LongSubstring::isMax(int a, int b){

       if(a > b) return true;

       return false;

}

LongSubstring::LongSubstring() {

       for(int i = 0; i < 26; i++)

       {

              hash[i] = -1;

       }

       maxlength = 1;

       start = 0;

}

LongSubstring::~LongSubstring(){

}

int LongSubstring::getLongestSubstring(string s) {

       // Start typing your C/C++ solution below

       // DO NOT write int main() function

       if(s.size() == 0)

              return 0;

      

       int temp = 0;

       map_to_hash(s[0], 0);

       for(int i = 1; i < s.size(); i++){

              if(get_hash_value(s[i]) < temp){

                     map_to_hash(s[i], i);          

              }

              else{

                     temp = get_hash_value(s[i]) + 1;

                     map_to_hash(s[i], i);              

              }            

              if (!isMax(maxlength,  i-temp+1)) update(i, temp);

       }

       out.assign(s,start,maxlength);

       return maxlength;

}

void LongSubstring::update(int cur, int oldpos){

       start = oldpos;

       maxlength = cur-oldpos+1;

}

void LongSubstring::map_to_hash(char ch, int pos){

       hash[ch – ‘a’] = pos;

}

int LongSubstring::get_hash_value(char ch) {

       return hash[ch – ‘a’];

}

void main() {

       string str;

       //char* ch;

       LongSubstring ls;

       str = “abcabcdbb”;

       //ch = &str[0];

       cout<<ls.out<<”      length: “<<ls.getLongestSubstring(str)<<endl;

}