【Java大数】hdu 5429 Geometric Progression

Source : hdu 5429 Geometric Progression

http://acm.hdu.edu.cn/showproblem.php?pid=5429

Problem Description

Determine whether a sequence is a Geometric progression or not.

In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio. For example, the sequence 2, 6, 18, 54, … is a geometric progression with common ratio 3. Similarly 10, 5, 2.5, 1.25, … is a geometric sequence with common ratio 1/2.

Examples of a geometric sequence are powers rk of a fixed number r, such as 2k and 3k. The general form of a geometric sequence is

a, ar, ar2, ar3, ar4, …

where r ≠ 0 is the common ratio and a is a scale factor, equal to the sequence’s start value.

Input

First line contains a single integer T(T≤20) which denotes the number of test cases.

For each test case, there is an positive integer n(1≤n≤100) which denotes the length of sequence,and next line has n nonnegative numbers Ai which allow leading zero.The digit’s length of Ai no larger than 100.

Output

For each case, output “Yes” or “No”.

题意

给n个数，判断能否构成等比数列（注意数的范围）

示例

Sample Input

4

1

0

3

1 1 1

3

1 4 2

5

16 8 4 2 1

Sample Output

Yes

Yes

No

Yes

思路

大数据，我用的JAVA！

参考代码

import java.io.*;
import java.util.*;
import java.math.*;

public class Main{
static BigInteger []a = new BigInteger [110];
static BigInteger zero = BigInteger.ZERO;
public static void main(String[] args){
Scanner cin = new Scanner(System.in);
int T = cin.nextInt();
while(T-- >0){
int n = cin.nextInt();
boolean has0 = false,all0 = true;
for(int i = 0; i < n; ++ i){
a[i] = cin.nextBigInteger();
if(a[i].compareTo(zero) == 0) has0 = true;
else all0 = false;
}
if(all0 == true){System.out.println("Yes");continue;}
if(has0 == true){System.out.println("No");continue;}
boolean ok = true;
for(int i = 2; i < n; ++ i){
if(a[i-1].multiply(a[i-1]).equals(a[i-2].multiply(a[i])) == false)
{
ok = false;
break;
}
}
if(ok) System.out.println("Yes");
else System.out.println("No");
}

}

}

加粗

Ctrl + B

斜体

Ctrl + I

引用

Ctrl + Q

插入链接

Ctrl + L

插入代码

Ctrl + K

插入图片

Ctrl + G

提升标题

Ctrl + H

有序列表

Ctrl + O

无序列表

Ctrl + U

横线

Ctrl + R

撤销

Ctrl + Z

重做

Ctrl + Y