Help me in solving P4149 problem

My issue

My first all 3 test cases are passed but hidden test cases are fail help me in these where my approach went wrong

My code

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


void test(){
  int n;cin>>n;
  vector<int>a(n);
  int sum=0;
  for(int i=0;i<n;i++){
    
    cin>>a[i];
    
    sum+= abs(a[i]);
    
  }
  cout<<sum<<endl;
  
  
  
}
int main() {
    int testCases;
    cin >> testCases;
    while (testCases--) {
      
        test();
      
      
    }
    return 0;
}

Problem Link: Maximise Sum Practice Coding Problem