Confusing Recursion Quiz - Different print in emulator than answer.

Question

The quiz says the answer should print 5 for returning 1 but when I run it I get 4.

when I return 2 it will print 5 and when I return 3 it prints 6.

when I do it on paper and show my work and return 1 I get 5.

what am I doing wrong?

https://code.sololearn.com/cp497z8PCrSp/?ref=app

https://code.sololearn.com/cjVco29jwSQ6/?ref=app

Answer 1

Your first link:
Try using "return fib(x-1)+fib(x-2)" in your else (line 6). Instead of "return fib(x-1)+(x-2)".

Now, if you print fib(4), it will return fib(3)+(4-2). The fib(3) will be recurrenced to fib(2)+(3-2). And so on till your get to your fib(1) in your if. The Fibonacci Sequence is defined by F(n)=F(n-1)+F(n-2).

This is what happens now:
print fib(4) returns fib(3)+(4-2)
=> returns (fib(2)+(3-2))+(4-2)
=> returns ((fib(1)+(2-2))+(3-2))+(4-2)
=> returns ((1)+(0))+(1))+(2)
=> returns 4

Your second link:
Same problem in line 6, as explained above.

And another problem in line 3: about the Fibonacci sequence itself.
The first two numbers in the Fibonacci sequence are 1 and 1 (or 0 and 1, but that's more math preference) and each subsequent number is the sum of the previous two. So it looks like this:
1,1,2,3,5,8,13,21,34,...

x is the position in the sequence. So the zero-th and the first position should be 1.
Thus line 3 should be "return 1" instead of "return 2".

I hope this clarifies a bit. :)

Answer 2

# 4
3 2
2 1 1 0
1 0
I take some time ,too. if you split it, you can find there are total five base cases(0 or 1).