题意 : 判断 n 个数组成的序列是否为等比数列；

思路: a[i]a[i] = a[i-1]a[i+1];

代码：

import java.util.Scanner;import java.math.*;public class Main {    public static void main(String args[]){        BigDecimal a,b,c;        Scanner cin = new Scanner(System.in);        int t = cin.nextInt();        while(t>0){            t--;            BigDecimal [] ar = new BigDecimal[110] ;            int n = cin.nextInt();            int cnt = 0;            for(int i=0;i