C++ 算法：计算混合复习获得的总能力值

#include #include

using namespace std;

int main() { int n; cin >> n;

vector<int> a(n);
for (int i = 0; i < n; i++) {
    cin >> a[i];
}

long long totalAbility = 0;
for (int i = 0; i < n-1; i++) {
    for (int j = i+1; j < n; j++) {
        totalAbility += a[i] * a[j];
    }
}

cout << totalAbility << endl;

return 0;

}