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javacomplexity-theorybiginteger

What complexity are operations on BigInteger?

What complexity are the methods multiply, divide and pow in BigInteger currently? There is no mention of the computational complexity in the documentation (nor anywhere else).

Solution

  • If you look at the code for BigInteger (provided with JDK), it appears to me that multiply(..) has O(n^2) (actually the method is multiplyToLen(..)). The code for the other methods is a bit more complex, but you can see yourself.

    Note: this is for Java 6. I assume it won't differ in Java 7.