java与高精度

1.头文件

import java.math.BigInteger;
import java.util.Scanner;

 

2.输入输出

输入：

Scanner cin = new Scanner(System.in);

while (cin.hasNextInt());

输出：

System.out.println(f[n]);

 

3.数组定义

BigInteger f[] = new BigInteger[105];

 

4.一些函数及应用

卡特兰数应用：hdu 1130,1131,1134

http://acm.hdu.edu.cn/showproblem.php?pid=1134

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        BigInteger f[] = new BigInteger[105];
        int i, n, num;
        f[1] = new BigInteger("1");
        for (i = 2; i < 105; i++) {
            num = 4 * i - 2;
            f[i] = f[i - 1].multiply(BigInteger.valueOf(num));
            f[i] = f[i].divide(BigInteger.valueOf(i + 1));
        }
        while (cin.hasNextBigInteger()) {
            n = cin.nextInt();
            if (n == -1)
                break;
            System.out.println(f[n]);
        }
    }
}

hdu 1063 Exponentiation：http://acm.hdu.edu.cn/showproblem.php?pid=1063

import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        BigDecimal R, r;
        String res;
        int i, n;
        while (cin.hasNextBigDecimal()) {
            r = new BigDecimal("1");
            R = cin.nextBigDecimal();
            n = cin.nextInt();
            for (i = 0; i < n; i++)
                r = r.multiply(R);
            r = r.stripTrailingZeros(); // 消除尾数0
            res = r.toPlainString(); // 大数->字符串
            if (res.startsWith("0.")) // 判断字符串是否以某字符串开始
                res = res.substring(1);
            System.out.println(res);
        }
    }
}

hdu 1316 How Many Fibs?:http://acm.hdu.edu.cn/showproblem.php?pid=1316

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int i, ans;
        BigInteger x, y, Zero;
        BigInteger f[] = new BigInteger[505];
        f[1] = new BigInteger("1");
        f[2] = new BigInteger("2");
        Zero = new BigInteger("0");
        
        for (i = 3; i < 505; i++)
            f[i] = f[i - 1].add(f[i - 2]);
        
        while (cin.hasNextBigInteger()) {
            x = cin.nextBigInteger();
            y = cin.nextBigInteger();
            if (x.compareTo(Zero) == 0 && y.compareTo(Zero) == 0)
                break;
            
            ans=0;
            for(i=1;i<505;i++)  //暴力查找
            {
                if(x.compareTo(f[i])<=0&&y.compareTo(f[i])>=0)
                    ans++;
            }
            System.out.println(ans);
        }
    }
}

hdu 1753 大明A+B:http://acm.hdu.edu.cn/showproblem.php?pid=1753

import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
    BigDecimal x,y;
        while(cin.hasNextBigDecimal())
        {
            x=cin.nextBigDecimal();
            y=cin.nextBigDecimal();
            x=x.add(y);
            //消除尾数0；防止高精度数表示成科学计数法
            System.out.println(x.stripTrailingZeros().toPlainString());
        }
    }
}