To remove the Duplicates from the given string (without sorting it)-CodePudding

The question is asking to remove duplicates from the string, I came up with a solution to remove duplicates but for that, I sorted the string. So I wanted to know is there a way of removing duplicates from a string without sorting the string.

Test Cases : 

"allcbcd" -> "alcbd"

My Code (the one in which string has to be sorted) :

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

string removeDup(string s)
{
   if (s.length() == 0)
   {
       return "";
   }

   sort(s.begin(), s.end());
   char ch = s[0];
   string ans = removeDup(s.substr(1));

   if (ch == ans[0])
   {
       return ans;
   }

   return (ch   ans);
}

int main()
{
   cout << removeDup("allcbbcd") << endl;

   return 0;
}

CodePudding user response：

Here is one way to do it without sorting (or using a recursive loop):

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

string removeDup(string s)
{
   string::size_type index = 0;
   string::iterator end = s.end();

   while (index < s.size()) {
       end = remove(s.begin() index 1, end, s[index]);
         index;
   } 

   s.erase(end, s.end());
   return s;
}

int main()
{
   cout << removeDup("allcbbcd") << endl;

   return 0;
}

Online Demo

CodePudding user response：

I goofed. The solution I provided was for python. But here is a c solution where users provide a few different stl methods.