Reverse a nested Array list Javascript

Question

What i want it to reverse a list from bottom to top. I used for loop of i--, but i coudn't make it work even by using the built in Reverse() function.

The rules are:

You cannot use the built-in reverse() function.
null is non-existent object, you may use an empty object instead if desired.
Your function should be able to reverse a list of values of any type.
You must use at least one array to solve the problem.

Original:

var list = {
   value: 1,
      next: {
         value: 2,
         next: {
            value: 3,
            next: null     
         }
      }
};

Reverse it to look like:

var list = {
   value: 3,
   next: {
     value: 2,
     next: {
       value: 1,
       next: null
     }
   }
};

Example Test Case:

function reverseList(list) {
    // return reversedList;
}

Arguments: { value: 1, next: { value: 2, next: { value: 3, next: null } } };
Returns: { value: 3, next: { value: 2, next: { value: 1, next: null } } };

Arguments: { value: "a", next: { value: "b", next: { value: "c", next: null } } };
Returns: { value: "c", next: { value: "b", next: { value: "a", next: null } } };

lucky you can't use reverse ... since there's absolutely no arrays in that data — Jaromanda X
– Jaromanda X, Commented Oct 14, 2020 at 1:49
This is called reversing a linkedlist and is just a coding interview problem that should never have to be used in real life. If this is a real problem in some code you wrote, you are using the wrong data structure. If you are trying to get help on a coding interview, implement the algorithm here(geeksforgeeks.org/reverse-a-linked-list) — Kyle DePace
– Kyle DePace, Commented Oct 14, 2020 at 1:54
Thank you @KyleDePace, ya, it is a question i was given to solve. Do you think it can be solved easily? maybe with the use of one or two functions? — muse
– muse, Commented Oct 14, 2020 at 2:09
Reverse a nested Array list Javascript as Jaromanda already said, there's no array anywhere in that data structure. That's a linked list. where did you get the term nested Array list from? 4. You must use at least one array to solve the problem. why? that's unnecesary overhead. — Thomas
– Thomas, Commented Oct 14, 2020 at 2:26
"it is a question i was given to solve." - Then it is either an interview Question or School learning task. Either way this is a task for you to research. I would suggest you could start by reading about Object.keys() — Aaron
– Aaron, Commented Oct 14, 2020 at 2:34

sandeep joshi · Accepted Answer · 2020-10-14 03:54:53Z

0

there is no array so you cant inbuilt reverse function. also searching for reverse a linked list on SO gave me this which I am referencing in code snippet.

var reverseLinkedList = function(linkedlist) {
  var node = linkedlist;
  var previous = null;

  while (node) {
    // save next or you lose it!!!
    var save = node.next;
    // reverse pointer
    node.next = previous;
    // increment previous to current node
    previous = node;
    // increment node to next node or null at end of list
    node = save;
  }
  return previous; // Change the list head !!!
}
var list = {
  value: 1,
  next: {
    value: 2,
    next: {
      value: 3,
      next: null
    }
  }
};
var linkedlist = reverseLinkedList(list);
console.log(JSON.stringify(linkedlist));

answered Oct 14, 2020 at 3:54

sandeep joshi

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