BigInteger.pow（BigInteger的）？ [英] BigInteger.pow(BigInteger)?

问题描述

我正在玩Java中的数字，想看看我能做多少。我的理解是BigInteger可以容纳一些无限大小，只要我的计算机有足够的内存来容纳这样的数字，对吗？

I'm playing with numbers in Java, and want to see how big a number I can make. It is my understanding that BigInteger can hold a number of infinite size, so long as my computer has enough Memory to hold such a number, correct?

我的问题是BigInteger .pow只接受一个int，而不是另一个BigInteger，这意味着我只能使用一个最多2,147,483,647的数字作为指数。是否可以使用BigInteger类？

My problem is that BigInteger.pow accepts only an int, not another BigInteger, which means I can only use a number up to 2,147,483,647 as the exponent. Is it possible to use the BigInteger class as such?

BigInteger.pow(BigInteger)

谢谢。

推荐答案

你可以写你自己的，使用重复的平方：

You can write your own, using repeated squaring:

BigInteger pow(BigInteger base, BigInteger exponent) {
  BigInteger result = BigInteger.ONE;
  while (exponent.signum() > 0) {
    if (exponent.testBit(0)) result = result.multiply(base);
    base = base.multiply(base);
    exponent = exponent.shiftRight(1);
  }
  return result;
}

可能不适用于负基数或指数。

might not work for negative bases or exponents.

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