hdu 5429 Geometric Progression（java 高精度+java输入外挂）

题意：

给一个序列判断其是否是等比数列，每个数字A[i]不小于100位

解析：

（1）存在0的时候要全都是0,才能是Yes，存在0但不全是0则是No
（2）不存在0，则A[i-1]*A[i+1]==A[i]*A[i]是否全都成立

my code

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

class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1000];
    private int curChar;
    private int numChars;

    public InputReader(InputStream stream) {
        this.stream = stream;
    }

    private int read() {
        if (numChars == -1)
            throw new UnknownError();
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            } catch (IOException e) {
                throw new UnknownError();
            }
            if (numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }

    public int readInt() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return res * sgn;
    }

    public int[] readIntArray(int length) {
        int[] res = new int[length];
        for (int i = 0; i < length; i++)
            res[i] = readInt();
        return res;
    }

    public int[][] readIntArray(int n, int m) {
        int[][] res = new int[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                res[i][j] = readInt();
        return res;
    }

    public long readLong() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        long res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return res * sgn;
    }

    public long[] readLongArray(int length) {
        long[] res = new long[length];
        for (int i = 0; i < length; i++)
            res[i] = readLong();
        return res;
    }

    public long[][] readLongArray(int n, int m) {
        long[][] res = new long[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                res[i][j] = readLong();
        return res;
    }

    public String readString() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        StringBuffer res = new StringBuffer();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isSpaceChar(c));
        return res.toString();
    }

    public String[] readStringArray(int length) {
        String[] res = new String[length];
        for (int i = 0; i < length; i++)
            res[i] = readString();
        return res;
    }

    public String next() {
        return readString();
    }

    private String readLine0() {
        StringBuffer buf = new StringBuffer();
        int c = read();
        while (c != '\n' && c != -1) {
            buf.appendCodePoint(c);
            c = read();
        }
        return buf.toString();
    }

    public String readLine() {
        String s = readLine0();
        while (s.trim().length() == 0)
            s = readLine0();
        return s;
    }

    public String readLine(boolean ignoreEmptyLines) {
        if (ignoreEmptyLines)
            return readLine();
        else
            return readLine0();
    }

    public BigInteger readBigInteger() {
        try {
            return new BigInteger(readString());
        } catch (NumberFormatException e) {
            throw new InputMismatchException();
        }
    }

    public char readCharacter() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        return (char) c;
    }

    public char[] readCharArray(int length) {
        char[] res = new char[length];
        for (int i = 0; i < length; i++)
            res[i] = readCharacter();
        return res;
    }

    public char[][] readCharArray(int n, int m) {
        char[][] res = new char[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                res[i][j] = readCharacter();
        return res;
    }

    public double readDouble() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        double res = 0;
        while (!isSpaceChar(c) && c != '.') {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        }
        if (c == '.') {
            c = read();
            double m = 1;
            while (!isSpaceChar(c)) {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                m /= 10;
                res += (c - '0') * m;
                c = read();
            }
        }
        return res * sgn;
    }

    public double[] readDoubleArray(int length) {
        double[] res = new double[length];
        for (int i = 0; i < length; i++)
            res[i] = readDouble();
        return res;
    }

    public double[][] readDoubleArray(int n, int m) {
        double[][] res = new double[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                res[i][j] = readDouble();
        return res;
    }

    private boolean isSpaceChar(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }
}

public class Main {
    static InputReader cin = new InputReader(System.in);

    static BigDecimal[] a = new BigDecimal[105];
    static int n;

    static boolean judge() {
        if (n == 1)
            return true;
        int cnt = 0;
        for (int i = 1; i <= n; i++) {
            if (a[i].compareTo(BigDecimal.ZERO) == 0)
                cnt++;
        }
        if (cnt > 0) {
            if (cnt == n)
                return true;
            else
                return false;
        }
        for (int i = 2; i < n; i++) {
            BigDecimal x = a[i].multiply(a[i]);
            BigDecimal y = a[i - 1].multiply(a[i + 1]);
            if (x.compareTo(y) != 0)
                return false;
        }
        return true;
    }

    public static void main(String[] args) throws IOException {
        int T;
        T = cin.readInt();
        while (T-- > 0) {
            n = cin.readInt();
            for (int i = 1; i <= n; i++) {
                a[i] = new BigDecimal(cin.next());
            }
            System.out.println(judge() ? "Yes" : "No");
        }
    }
}