/**
* Returns the polynomial obtained by adding the given polynomial p to this polynomial - DOES NOT
* change this polynomial
*
* @param p Polynomial to be added
* @return A new polynomial which is the sum of this polynomial and p.
*/
public Polynomial add(Polynomial p) {
// Returns other list if adding zero to it
if (p.poly == null) return this;
else if (this.poly == null) return p;
Node list1 = this.poly;
Node list2 = p.poly;
Polynomial newList = new Polynomial();
// Iterates through both lists
while (list1 != null && list2 != null) {
if (list1.term.degree == list2.term.degree) { // Checks for similar degrees between lists
if (list1.term.coeff + list2.term.coeff
== 0) { // Checks if the coefficients total 0, skips making a node
list1 = list1.next;
list2 = list2.next;
} else { // If coeff total is not 0, makes a new node adding them
float newCoeff = list1.term.coeff + list2.term.coeff;
Node n = new Node(newCoeff, list1.term.degree, null);
newList.addToEnd(n);
list1 = list1.next;
list2 = list2.next;
}
}
// If currently evaluated nodes are not equal, then there are no like degrees between lists
// Adds new node with the currently evaluated term's values and increments respective pointer
else if (list1.term.degree > list2.term.degree) {
Node n = new Node(list2.term.coeff, list2.term.degree, null);
newList.addToEnd(n);
list2 = list2.next;
} else if (list2.term.degree > list1.term.degree) {
Node n = new Node(list1.term.coeff, list1.term.degree, null);
newList.addToEnd(n);
list1 = list1.next;
}
}
// Deals with uneven list: whatever list isn't finished parsing is simply added to end of
// newList
Node tmp = null;
if (list1 != null) tmp = list1;
else if (list2 != null) tmp = list2;
while (tmp != null) {
Node n = new Node(tmp.term.coeff, tmp.term.degree, null);
newList.addToEnd(n);
tmp = tmp.next;
}
return newList;
}
// Helper method to sort an unsorted linked list in ascending order. All like degrees will be next
// to each other.
private void sort() {
Polynomial newList = new Polynomial();
for (Node tmp1 = poly; tmp1 != null; tmp1 = tmp1.next) {
Node n = new Node(tmp1.term.coeff, tmp1.term.degree, null);
if (newList.poly == null) newList.poly = n;
else {
for (Node tmp2 = newList.poly; tmp2 != null; tmp2 = tmp2.next) {
if (tmp2.next == null) {
tmp2.next = n;
break;
} else if (tmp2.next.term.degree > n.term.degree) {
n.next = tmp2.next;
tmp2.next = n;
break;
}
}
}
}
poly = newList.poly;
}
/**
* Returns the polynomial obtained by multiplying the given polynomial p with this polynomial -
* DOES NOT change this polynomial
*
* @param p Polynomial with which this polynomial is to be multiplied
* @return A new polynomial which is the product of this polynomial and p.
*/
public Polynomial multiply(Polynomial p) {
// If multiplying by zero, return the null list
if (p.poly == null) return p;
else if (this.poly == null) return this;
Polynomial newList = new Polynomial();
// Nested loop to multiply terms. Multiplies first term by every term in second list and so on.
for (Node list1 = this.poly; list1 != null; list1 = list1.next) {
for (Node list2 = p.poly; list2 != null; list2 = list2.next) {
Node n =
new Node(
list1.term.coeff * list2.term.coeff, list1.term.degree + list2.term.degree, null);
newList.addToEnd(n);
}
}
// sorts newList in ascending order and then combines like degrees.
newList.sort();
newList.compress();
return newList;
}
