#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define mk make_pair
#define S second
#define F first
#define int long long
void solve(){
	int n;
	cin>>n;
	int a[n];
	int ans=0;
	bool nem=0, has=0;
	int sum=0;
	for(int i=0; i<n; i++){
        cin>>a[i];
        if(a[i]>0) nem=1;
        else has=1;
        sum+=abs(a[i]);
	}
	if(n==1){
        cout<<a[0]<<endl;
        return;
	}
	if(nem and has){
        cout<<sum<<endl;
	}
	else{
        int mn=1e18;
        for(int i=0; i<n; i++){
            mn=(a[i]-a[(i+1)%n]);
            ans=max(ans,sum-a[i]-a[(i+1)%n]-mn);
        }
        cout<<ans<<endl;
        //cout<<sum-mn<<endl;
	}
}
signed main(){
	int t;
	cin>>t;
	while(t-- ) solve();

}