Java Program Fibonacci Sequence

Question

I am writing a \"simple\" program to determine the Nth number in the Fibonacci sequence. Ex: the 7th number in the sequence is: 13. I have finished writing the program, it

Answer 1

Too slow...

Better: (JavaScript example)

function fibonacci(n) {
    var a = 0, b = 1;

    for (var i = 0; i < n; i++) {
        a += b;
        b = a - b;
    }
    return a;
}

Answer 2

My solution using Java 8 Stream:

public class Main {
    public static void main(String[] args) {
        int n = 10;
        Fibonacci fibonacci = new Fibonacci();
        LongStream.generate(fibonacci::next)
                .skip(n)
                .findFirst()
                .ifPresent(System.out::println);
    }
}

public class Fibonacci {
    private long next = 1;
    private long current = 1;

    public long next() {
        long result = current;
        long previous = current;
        current = next;
        next = current + previous;
        return result;
    }
}

Answer 3

The problem is not JAVA, but the way you are implementing your Fibonacci algorithm. You are computing the same values many times, which is slowing your program.

Try something like this : Fibonacci with memoization