Utopian Tree Exercise, Tree of Life etc. etc

Question

Good morning! I am taking the Santander course, and the last challenge is the famous calculation of the height of the tree of life. I have a very specific problem. Rather, it follows the statement:

Utopian trees grow in a particular way in two cycles:

each spring double its size each summer grow one meter if Laura plant a utopian tree with one meter, in late autumn, which would be its height after N cycles?

Some examples:

si N = 0, your height will be 1 meter (nothing has grown);

si N = 1, its height will be 2 meters (doubled the height in spring)

si N = 2, its height will be 3 meters (grew one meter more in summer)

si N = 3, its height will be 6 meters (doubled the height in spring next)

And so ... Write the function alturaArvoreUtopica, which uses a amount of growth cycles, and return the height resulting from the laura tree.

So, since the platform is kind of bad, I usually do the code in Codepen, test and then move to the platform in the course. My code looked like this:

function alturaArvoreUtopica (ciclos) {
  var altura = 1;
  if (ciclos == 0) {
    altura = 1;
  } else {
  for (var i=1; i<=ciclos; i++) {
    if (i % 2 == 0) {
      altura += 1;
    } else {
      altura = altura*2;
    }
    }
    return altura  
  }}

In Codepen the code worked well in all tests, however, when running the code on the platform appeared the following error: Expected Undefined to Equal 1.

Does anyone know what might have happened? Is it some detail I missed or should I redo the code differently?

Answer 1

You forgot the Return for case 0. Change to:

function alturaArvoreUtopica (ciclos) {
  var altura = 1;
  if (ciclos == 0) {
    altura = 1;
    return altura; // aqui
  } else {
    for (var i=1; i<=ciclos; i++) {
      if (i % 2 == 0) {
        altura += 1;
      } else {
        altura = altura*2;
      }
    }
    return altura;
  }
}

console.log(alturaArvoreUtopica(0))

From what you said and the message, your code probably went through a test cycle with different values. When you call the original function with the value 0 the return is coming Undefined. It should be just that. Note that the last Return is inside Else.

Doing the function like this makes it easier to read and understand:

function alturaArvoreUtopica (ciclos) {
  var altura = 1;
  if (ciclos == 0) 
    altura = 1;
  else
    for (var i=1; i<=ciclos; i++) {
      if (i % 2 == 0)
        altura += 1;
      else
        altura = altura*2;
    }
  return altura;
}

And this is for you to study a little:

let alturaArvoreUtopica2 = (ciclos) => {
  let altura = 1;
  if (!ciclos) 
    return 1;

  [...Array(++ciclos).keys()]
    .slice(1)
    .forEach((_, i)=>(i + 1)%2 ? altura *= 2 : altura++);
  return altura;
}