Factorial (mind the size)

n! is 1 × 2 × … × n, and 0! is 1. It grows fast — 20! is over two billion billion — so the method returns a long, not an int, or the answer would overflow. Multiply from 2 up to n.

Complete factorial(int n) returning n! as a long (so large values fit). factorial(0) is 1. Assume 0 <= n <= 20.

public class Math2 {
    public static long factorial(int n) {
        return 0;   // change this
    }
}

Click Run to see the output here.

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Factorial (mind the size)

Factorial (mind the size)

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