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#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vpi = vector<pi>;
using vi = vector<int>;
using vll = vector<long long>;
using mpii = map<int, int>;
using mpll = map<ll, ll>;
using db = long double;
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define lb lower_bound
#define ub upper_bound
const int MOD = (int)1e9 + 7;
const db PI = acos((db)-1);
const int dx[4]{1, 0, -1, 0};
const int dy[4]{0, 1, 0, -1};
//pretty printing
template<typename K, typename V>
void printm(const map<K, V> &mp) {
cerr << "{" << endl;
for (auto p : mp) {
cerr << " { " << p.first << " : " << p.second << " }\n";
}
cerr << "}" << endl;
}
template<typename T>
void printv(const vector<T> &v) {
cerr << "[";
for (int i = 0; i < v.size(); i++) {
if (i == v.size() - 1) {
cerr << v[i];
} else {
cerr << v[i] << ", ";
}
}
cerr << "]\n";
}
template<typename T>
void printvv(const vector<vector<T>> &v) {
cerr << "[\n";
for (auto &vec : v) {
cout << " ";
printv(vec);
}
cerr << "]\n";
}
void print() {
cerr << "\n";
}
template<typename T, typename... TS>
void print(T val, TS... vals) {
cerr << val << " ";
print(vals...);
}
/* stuff you should look for:
---------------------------
* special cases (n=1?)
* int overflow, array bounds
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
*/
/*
* Ideally we want them all to be positive
* If we can't get them all to be positive we want to flip the largest numbers in absloute
* The 0 can be a joker because flipping its sign is meaningless anyways
*/
void solve() {
int n;
cin >> n;
vll v(n);
for (auto &x : v) cin >> x;
int neg = 0;
for (auto x : v) {
neg += (x < 0);
}
ll sum = 0;
if (neg % 2 == 0) {
for (auto x : v) {
if (x < 0) {
sum += -x;
} else {
sum += x;
}
}
} else {
for (auto &x : v) {
if (x < 0) {
x = -x;
}
}
for (auto x : v) {
sum += x;
}
sum -= *min_element(all(v)) * 2;
}
cout << sum << '\n';
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int tt;
cin >> tt;
while(tt--) {
solve();
}
}
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