Codeforces Round #780 (Div. 3) 1660C - Get an Even String Solution

  Problem Link :  https://codeforces.com/contest/1660/problem/C

Solution in C++:

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

#include <bits/stdc++.h>

using namespace std;

int main()

{

    long long  i,t,j;

    cin>>t;

    while(t--)

    {

        string s,r;

        map<char,int>mp;

        cin>>s;

        for(i=0; i<s.size()-1; i++)

        {

          if(s[i]==s[i+1])

          {

              r+=s[i];

              r+=s[i+1];

              i++;

          }

          else

          {

              while(i<s.size()&&mp[s[i]]!=1)

              {

                  mp[s[i]]=1;

                  i++;

              }

              if(i<s.size())

              {

                  r+=s[i];

                  r+=s[i];

              }

              mp.clear();

          }

        }

         cout<<s.size()-r.size()<<endl;

    }

}