CF1917A Least Product

You are given an array of integers $ a_1, a_2, \dots, a_n $ . You can perform the following operation any number of times (possibly zero): - Choose any element $ a_i $ from the array and change its value to any integer between $ 0 $ and $ a_i $ (inclusive). More formally, if $ a_i < 0 $ , replace $ a_i $ with any integer in $ [a_i, 0] $ , otherwise replace $ a_i $ with any integer in $ [0, a_i] $ . Let $ r $ be the minimum possible product of all the $ a_i $ after performing the operation any number of times. Find the minimum number of operations required to make the product equal to $ r $ . Also, print one such shortest sequence of operations. If there are multiple answers, you can print any of them.

Each test consists of multiple test cases. The first line contains a single integer $ t $ ( $ 1 \leq t \leq 500 $ ) - the number of test cases. This is followed by their description. The first line of each test case contains the a single integer $ n $ ( $ 1 \leq n \leq 100 $ ) — the length of the array. The second line of each test case contains $ n $ integers $ a_1, a_2, \ldots, a_n $ ( $ -10^9 \leq a_i \leq 10^9 $ ).

For each test case: - The first line must contain the minimum number of operations $ k $ ( $ 0 \leq k \leq n $ ). - The $ j $ -th of the next $ k $ lines must contain two integers $ i $ and $ x $ , which represent the $ j $ -th operation. That operation consists in replacing $ a_i $ with $ x $ .

In the first test case, we can change the value of the first integer into $ 0 $ and the product will become $ 0 $ , which is the minimum possible. In the second test case, initially, the product of integers is equal to $ 2 \cdot 8 \cdot (-1) \cdot 3 = -48 $ which is the minimum possible, so we should do nothing in this case.