finding repeated numbers using merge sort

#include <bits/stdc++.h>

using namespace std;
void merge(vector<int> &v,int left,int right)
{
    int mid=(left+right)/2;

    int p1=left,p2=mid+1,k=0;
    vector<int> temp(right-left+1);
    while(p1<mid+1&&p2<right+1)
    {
        if(v[p1]<v[p2])
        temp[k++]=v[p1++];
        else
        temp[k++]=v[p2++];
    }
    while(p1<mid+1)
    temp[k++]=v[p1++];
    while(p2<right+1)
    temp[k++]=v[p2++];
    k=0;
    for(int i=left;i<=right;i++)
    v[i]=temp[k++];


}
void MS(vector<int> &v,int left,int right)
{
    if(left==right)
    return;


    int mid=(left+right)/2;

    MS(v,left,mid);//left half sorting
    MS(v,mid+1,right);//right half sorting
    merge(v,left,right);//merging the two sorted parts
    /* for(auto x:v)
    cout<<x;
    cout<<endl;*/
}
int main()
{
    int tc;
    cin>>tc;
    vector<int> c(tc);
    vector<vector<int>> z;
    for(int i=0;i<tc;i++)
     {

         cin>>c[i];
         vector<int> v(c[i]);
         for(int j=0;j<c[i];j++)
         {
             int temp;
             cin>>temp;
             v[j]+=temp;
         }

         MS(v,0,c[i]-1);
        /* for(auto x:v)
         {
             cout<<x<<" ";
         }cout<<endl;*/
         z.push_back(v);
     }


   for(int i=0;i<tc;i++)
    {
        set<int> s;
        vector<int> v=z[i];
      for(int j=0;j<c[i];j++)
      {
          cout<<v[j]<<" ";
         if(v[j]==v[j-1])
         s.insert(v[j]);
      }cout<<endl;
     /* for(auto x:s)
      cout<<x<<" ";
      cout<<endl;*/
    }
}