13:I[87,["736","static/chunks/89fc4f0e-9e200ae6a0166583.js","401","static/chunks/363642f4-32903b9154b7835a.js","153","static/chunks/153-58eddeb032cc4608.js","131","static/chunks/131-05ce00cfd760e12b.js","87","static/chunks/87-b76b60eef573119a.js","286","static/chunks/app/problem/%5Bid%5D/page-45cf3875257fc32e.js"],"Header"] 14:I[1742,["736","static/chunks/89fc4f0e-9e200ae6a0166583.js","401","static/chunks/363642f4-32903b9154b7835a.js","153","static/chunks/153-58eddeb032cc4608.js","131","static/chunks/131-05ce00cfd760e12b.js","87","static/chunks/87-b76b60eef573119a.js","286","static/chunks/app/problem/%5Bid%5D/page-45cf3875257fc32e.js"],"ProblemView"] 15:T6cd,

You are given $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$. For any real number $$$t$$$, consider the complete weighted graph on $$$n$$$ vertices $$$K_n(t)$$$ with weight of the edge between vertices $$$i$$$ and $$$j$$$ equal to $$$w_{ij}(t) = a_i \cdot a_j + t \cdot (a_i + a_j)$$$.

Let $$$f(t)$$$ be the cost of the minimum spanning tree of $$$K_n(t)$$$. Determine whether $$$f(t)$$$ is bounded above and, if so, output the maximum value it attains.

Input

The input consists of multiple test cases. The first line contains a single integer $$$T$$$ ($$$1 \leq T \leq 10^4$$$) — the number of test cases. Description of the test cases follows.

The first line of each test case contains an integer $$$n$$$ ($$$2 \leq n \leq 2 \cdot 10^5$$$) — the number of vertices of the graph.

The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$-10^6 \leq a_i \leq 10^6$$$).

The sum of

Parametric MST

Examples