Gotta love factorials

Computer Science Level 3

This is a method in Java that returns the factorial of the Integer n :

public Double factorial(Integer n){
    if(n == 0) return 1;
    Integer c = n;
    while(c>1){
        c--;
        n *= c;
    }
    return n;
}

This is pretty big. We may want to reduce the number of lines. What's the minimum number of lines you can write this method's body , without changing its signature and returning exactly the same result?

4 2 1 3

1 solution

João Arruda
Apr 18, 2016

Using recursion and ternary operands we can reduce the body to $\boxed{1}$ line:

public Double factorial(Integer n){
    return (n <= 1) ? 1 : n * factorial(n--);
}

Gotta love factorials

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