Be Positive

## 题目描述 有一个包含nnn个整数的数组,你需要找到一个非零整数$d(-10^3\leq d \leq 10^3)$，使数组中的每一个数组除以d的商中至少有一半为正数(即至少有$\frac{n}{2}$个)注意:"正数"只要求商大于0,不要求一定是整数。如果有多个$d$满足条件，输出其中的任意一个,如果没有这样的$d$则输出$0$。 ## 输入输出格式 ### 输入格式: 第一行包含一个整数$n$,表示数组中元素的数量 第二行包含由$n$个整数,数之间由一个空格隔开。$a_1,a_2,a_3,...,a_n(-10^3\leq a_i \leq 10^3)$ ### 输出格式: 一个满足题目描述的整数$d(-10^3\leq d \leq 10^3,d \neq 0)$,如果有多个$d$满足条件,你可以打印其中任何一个。如果没有满足条件的整数$d$,输出0

You are given an array of $ n $ integers: $ a_1, a_2, \ldots, a_n $ . Your task is to find some non-zero integer $ d $ ( $ -10^3 \leq d \leq 10^3 $ ) such that, after each number in the array is divided by $ d $ , the number of positive numbers that are presented in the array is greater than or equal to half of the array size (i.e., at least $ \lceil\frac{n}{2}\rceil $ ). Note that those positive numbers do not need to be an integer (e.g., a $ 2.5 $ counts as a positive number). If there are multiple values of $ d $ that satisfy the condition, you may print any of them. In case that there is no such $ d $ , print a single integer $ 0 $ . Recall that $ \lceil x \rceil $ represents the smallest integer that is not less than $ x $ and that zero ( $ 0 $ ) is neither positive nor negative.

The first line contains one integer $ n $ ( $ 1 \le n \le 100 $ ) — the number of elements in the array. The second line contains $ n $ space-separated integers $ a_1, a_2, \ldots, a_n $ ( $ -10^3 \le a_i \le 10^3 $ ).

Print one integer $ d $ ( $ -10^3 \leq d \leq 10^3 $ and $ d \neq 0 $ ) that satisfies the given condition. If there are multiple values of $ d $ that satisfy the condition, you may print any of them. In case that there is no such $ d $ , print a single integer $ 0 $ .

5
10 0 -7 2 6

4

7
0 0 1 -1 0 0 2

0

In the first sample, $ n = 5 $ , so we need at least $ \lceil\frac{5}{2}\rceil = 3 $ positive numbers after division. If $ d = 4 $ , the array after division is $ [2.5, 0, -1.75, 0.5, 1.5] $ , in which there are $ 3 $ positive numbers (namely: $ 2.5 $ , $ 0.5 $ , and $ 1.5 $ ). In the second sample, there is no valid $ d $ , so $ 0 $ should be printed.