Merkkijono

input/code.cpp: In function 'int main()':
input/code.cpp:8:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<s.size(); ++i){
                          ^
input/code.cpp:16:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while (j<s.size() && s[i]==s[j]) ++j;
                         ^

#include <iostream>
using namespace std;
string s;
string s2;
 
int main(){
  cin >> s;
  for (int i=0; i<s.size(); ++i){
    if (s2.size()==0){
      s2+=s[i];
      continue;
    }else{
      if (s2[s2.size()-1]==s[i]){
        s2=s2.substr(0, s2.size()-1);
        int j=i;
        while (j<s.size() && s[i]==s[j]) ++j;
        i=j-1;
      }else{
        s2+=s[i];
      }
    }
  }
  cout << s2 << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED