public void MakesNewObjects(NodeWithRandom input)
{
NodeWithRandom copied = ListCopier.CopyRandomList(input);
while (input != null)
{
copied.Should().NotBe(input);
input = input.next;
copied = copied.next;
}
}
// Copy List with Random Pointer
// A linked list is given such that each node contains an additional random pointer
// which could point to any node in the list or null.
// Return a deep copy of the list.
// Runtime: 88 ms, faster than 99.61% of C# online submissions
// https://leetcode.com/problems/copy-list-with-random-pointer/
public static NodeWithRandom CopyRandomList(NodeWithRandom head)
{
if (head == null)
{
return(null);
}
NodeWithRandom preHeadCopy = new NodeWithRandom(-1);
NodeWithRandom current = head;
NodeWithRandom currentCopy = preHeadCopy;
var index = new Dictionary <NodeWithRandom, NodeWithRandom>();
while (current != null)
{
currentCopy.next = new NodeWithRandom(current.val);
currentCopy = currentCopy.next;
index[current] = currentCopy;
current = current.next;
}
current = head;
NodeWithRandom headCopy = preHeadCopy.next;
currentCopy = headCopy;
while (current != null)
{
currentCopy.random = current.random == null ? null : index[current.random];
currentCopy = currentCopy.next;
current = current.next;
}
return(headCopy);
}
public void PreservesValues(NodeWithRandom input)
{
string initialListValues = input.PrintValues();
ListCopier.CopyRandomList(input).PrintValues().Should().Be(initialListValues);
}
