Linked List

This is a sample problem using a Linked List.

The duplicate removal algorithm is implemented with an O(n) solution using a Map:

1class LinkedList {
2 ...
3
4  removeDuplicates() {
5    let previouslySeen  = new Map();
6
7    let iterations      = this.count;
8    let current         = this.head;
9    let prev            = this.head;
10
11    for (let i = 0; i < iterations; i++) {
12      if (previouslySeen.has(current.value)) {
13        if (current.next) {
14          prev.next = current.next;
15        } else {
16          prev.next = null;
17        }
18
19        this.decrementCount();
20      } else {
21        previouslySeen.set(current.value, current);
22        prev = current;
23      }
24
25      current = current.next;
26    }
27  }
28
29 ...
30}
31