Remove elements from singly linked list (javascript)

Question

I'm doing a CodeFights problem, trying to remove elements from a singly linked list that has the value k.

Below is what I have (l is the list and k is the value):

function removeKFromList(l, k) {
    //figure out the head of the new list so we can reference it later
    var head = l;

    while (head.value === k){
        head = head.next;
    }

    var node = head;
    var temp = null;

    while (node && node !== null) {
        if (node.next.value === k){
            temp = node.next.next;
            node.next.next = null;
            node.next = temp;
        }
        node = node.next; 
        console.log("+++", head)
    }

    console.log("---", head)  
}

The CodeFight test cast is 3 -> 1 -> 2 -> 3 -> 4 -> 5. The final result would have been 1 -> 2 -> 4 -> 5. But my '---' console log keeps returning "Empty" (according to the CodeFights console).

My '+++' console log returns the correct head with element each loop.

I've been pulling my hair out over this, any idea what is missing here?

Answer 1

You need to return the list if you delete the first node.

Then you need a loop for taking the next not while the value is not found.

At last you need a check if the last node exist and if the value is found, then assign the next node to the last next property.

function removeNode(list, value) {
    var node = list,
        last;

    if (node && node.value === value) {
        return node.next;
    }

    while (node && node.value !== value) {
        last = node,
        node = node.next;
    }
    if (last && node.value === value) {
        last.next = node.next;
    }
    return list;
}

var list = { value: 1, next: { value: 2, next: { value: 3, next: { value: 4, next: { value: 5, next: { value: 6, next: { value: 7, next: null } } } } } } };

list = removeNode(list, 5);
console.log(list)

list = removeNode(list, 1);
console.log(list)

list = removeNode(list, 7);
console.log(list)

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