/*
* add (S, x):
* Adds the element x to a set S, if it is not present already.
* No return value.
*/
static void add(ref SetList S, int x)
{
/* if the element is already in the list,
* or if it is equal or less than zero,
* it will not be added to the list */
if (is_element_of(x, S) || x <= 0) {
return;
}
/* Creates a new node
* and fills it with value x
*/
SetNode add = new SetNode();
add.data = x;
/* If the list is empty,
* add it as first node in the list
*/
if (is_empty(S)) {
S.first = add;
}
/* If the list isn't empty,
* Iterate through list until the end
* and add the new node */
else {
SetNode node = S.first;
while (node.next != null) {
node = node.next;
}
node.next = add;
}
}
/*
* union( S, T ):
* returns the "union" of sets S and T
*/
static SetList union(SetList S, SetList T)
{
SetNode node_s = new SetNode();
node_s = S.first;
SetNode node_t = new SetNode();
node_t = T.first;
/* New SetList container for resulting set */
SetList union = new SetList();
/* adds elements of set S to the union set */
while (node_s != null) {
/* Potential duplicates are already handled by the add() procedure */
add(ref union, node_s.data);
/* Go to next iteration */
node_s = node_s.next;
}
/* Add all elements from set T to union set */
while (node_t != null) {
add(ref union, node_t.data);
node_t = node_t.next;
}
/* Return the final list */
return union;
}