汉诺塔问题的移动次数可以用H(n) = 2^n - 1来表示
由于2^64次方超出了long的表示范围,所以用BigInteger 来存储这个大整数,代码如下:
public class C_1_27 {
public static void main(String[] args) {
System.out.println(BigInteger.valueOf(2).pow(64).subtract(BigInteger.valueOf(1)).toString());
}
对于BigInteger用法的扩展如下:
//从键盘输入BigInteger类型数据
Scanner sc = new Scanner(System.in);
BigInteger bi = sc.nextBigInteger();
//直接获取 valueOf(),x=2,y=1
BigInteger x = BigInteger.valueOf(2);
BigInteger y = BigInteger.valueOf(1);
//2的64次方 pow()
BigInteger pow=x.pow(64);
//subtract() 减法:x-y:x.subtract(y)
BigInteger re1 = x.subtract(y);
//加乘除
BigInteger re2 = x.add(y);
BigInteger re3 = x.multiply(y);
BigInteger re4 = x.divide(y);
//mod()和remainder()都是取余
BigInteger re5 = x.mod(y);
BigInteger re7 = x.remainder(y);
System.out.println(re5+" "+re7);
//abs()绝对值
BigInteger re6 = x.abs();
//toString()将BigInteger 变成字符串序列
String re = re1.toString();
//比较大小x.compareTo(y) ==0 相等;<0 x小于y ; >0 x大于y
if (x.compareTo(y) == 0) {
System.out.println("x与y相等");
}else if (x.compareTo(y) < 0) {
System.out.println("x小于y");
}else if (x.compareTo(y) > 0) {
System.out.println("x大于y");
}