Help me in solving P4149 problem

help
,
1

My issue

why my code is ffailing I can’t understand

My code

#include <bits/stdc++.h>
using namespace std;

int main() {
	int t;
	 cin>>t;
	  while(t--){
	      int n;
	       cin>>n;
	       vector<int>arr(n);
	       for(int i=0;i<n;i++){
	           cin>>arr[i];
	       }
	       sort(arr.begin(),arr.end());
	     long long int  count=0,sum=0;
	       for(int i=0;i<n;i++){
	           if(arr[i]<=0){
	               count++;
	           }
	       }
	       if(count%2==0){
	           for(int i=0;i<count;i++){
	               arr[i]=abs(arr[i]);
	           }
	       }else{
	           for(int i=0;i<count-1;i++){
	               arr[i]=abs(arr[i]);
	           }
	       }
	       for(int i=0;i<n;i++){
	           sum+=arr[i];
	       }
	       cout<<sum<<endl;
	  }

}

Problem Link: Maximise Sum Practice Coding Problem