B"You are given a sequence a_1, a_2, ... , a_n consisting of n pairwise distinct positive integers. Find <= ft lfloor frac n 2 right rfloor different pairs of integers x and y such that: Note that some x or y can belong to multiple pairs. lfloor x rfloor denotes the floor function -- the largest integer less than or equal to x . x~mod~y denotes the remainder from dividing x by y . If there are multiple solutions, print any of them. It can be shown that at least one solution always exists. The first line contains a single integer t ( 1 <= t <= 10^4 ) -- the number of testcases. The first line of each testcase contains a single integer n ( 2 <= n <= 2 cdot 10^5 ) -- the length of the sequence. The second line of each testcase contains n integers a_1, a_2, ... , a_n ( 1 <= a_i <= 10^6 ). All numbers in the sequence are pairwise distinct. The sum of n over all testcases doesn't exceed 2 cdot 10^5 . The answer for each testcase should contain <= ft lfloor frac n 2 right rfloor different pairs of integers x and y such that x neq y , x and y appear in a and x~mod~y doesn't appear in a . Print the pairs one after another. You can print the pairs in any order. However, the order of numbers in the pair should be exactly such that the first number is x and the second number is y . All pairs should be pairwise distinct. If there are multiple solutions, print any of them. In the first testcase there are only two pairs: (1, 4) and (4, 1) . <= ft lfloor frac 2 2 right rfloor=1 , so we have to find one pair. 1~mod~4=1 , and 1 appears in a , so that pair is invalid. Thus, the only possible answer is a pair (4, 1) . In the second testcase, we chose pairs 8~mod~2=0 and 8~mod~4=0 . 0 doesn't appear in a , so that answ"...