Using the Java List to implement polynomial addition, multiply

Package Com.learn.algorithm.ploy;import Java.util.linkedlist;import Java.util.list;import java.util.Scanner;/** * Polynomial-related Operations */public class Ploy {public static void main (string[] args) {list<node> La = init (); List<node> Lb = init (); System.out.println (Polymulti (LA,LB));} private static list<node> init () {list<node> poly = new linkedlist<node> (); Scanner sc = new Scanner (system.in); System.out.println ("Enter the coefficients and parameters (for example, a-B indicates ax^b, the input 0,0 ends.) ): "); (true) {String line = Sc.nextline (); if (vaildate line) {string[] split = Line.split (", "); int coefficient = in Teger.parseint (split[0]); int exponential = Integer.parseint (split[1]); if (coefficient = = 0 && exponential = = 0) { break;} Poly.add (new Node (coefficient, exponential));} else {System.out.println ("[" + Line + "] entered incorrectly");}} SYSTEM.OUT.PRINTLN (poly); return poly;} /** * Polynomial addition * @param La * @param Lb * @return */public static list<node> polyPlus (list<node> LA,LIST&LT;NODE&G T LB) {list<node> Lc =New linkedlist<> (); int Sa = La.size (), Sb=lb.size (), Ia=0,ib=0;while (IA < Sa && IB < Sb) {if (La.get (i a). Getexponential () < Lb.get (IB). Getexponential ()) {Lc.add (La.get (IA)); ia + +;} else if (La.get (IA). Getexponential ( ) = = Lb.get (ib). Getexponential ()) {int Coe = La.get (ia). Getcoefficient () + Lb.get (IB). Getcoefficient (); if (Coe! = 0) {Lc. Add (New Node (Coe,la.get (IA). Getexponential ()));} IA + +, IB + +;} else {Lc.add (Lb.get (IB)); IB + +;}} while (IA < Sa) {Lc.add (La.get (ia++));} while (IB < Sb) {Lc.add (Lb.get (ib++));} return Lc;} /** * Polynomial addition (unordered) * @param La * @param Lb * @return */public static list<node> polyplus_update (list<node> la,lis T<node> Lb) {int Sa = La.size (), Sb=lb.size (), Ia=0,ib=0;while (IA < Sa) {node node = La.get (IA); Node nodebyexp = Getnodebyexp (Lb,node.getexponential ()), if (nodebyexp! = null) {if (node.getcoefficient () + nodebyexp.ge Tcoefficient () = = 0) {lb.remove (nodebyexp);} else{nodebyexp.setcoefficient (Node.getcoefficient () + nodebyexp.getcoefficient ());}} else {lb.add (node);} ia + +;} return Lb;} /** * Polynomial multiplication * @param La * @param Lb * @return */public static list<node> polymulti (list<node> la,list<node& Gt LB) {list<node> Lc = new linkedlist<> (), int Sa = La.size (), Sb=lb.size (), Ia=0,ib=0;while (IA < Sa) {IB = 0; Node Na = La.get (IA), while (IB < Sb) {Node Nb = Lb.get (IB); int exp = nb.getexponential () + na.getexponential ();//exponential addition in  T Coe = nb.getcoefficient () * na.getcoefficient ();//coefficients multiplied by node Nodebyexp = Getnodebyexp (LC, exp); if (nodebyexp! = null) {if (Coe + nodebyexp.getcoefficient () = = 0) {Lc.remove (nodebyexp);} Else{nodebyexp.setcoefficient (coe+ nodebyexp.getcoefficient ());}} else {lc.add (new Node (COE,EXP));} IB + +;} ia + +;} return Lc;}  /** * search for corresponding items based on coefficients, no return null * @param p * @param exp * @return */public static Node getnodebyexp (list<node> P,integer EXP) {if (exp = = NULL | | p = = NULL) {return null;} for (Node node:p) {if (node.exponential = = exp) {return Node;}} Return null;} /** * Verify the legitimacy of the input string * @param s * @return */public static Boolean vaildate (string s) {return s.matches ("[-]{0,1}[0-9]+[,]{1}[0 -9]+ ");}} /** entity class * */class Node {integer coefficient = 0;//coefficient Integer exponential = 0;//Index public node (integer coefficient,integer E xponential) {this.coefficient = Coefficient;this.exponential = exponential;} Public Integer getcoefficient () {return coefficient;} public void setcoefficient (Integer coefficient) {this.coefficient = coefficient;} Public Integer getexponential () {return exponential;} public void setexponential (Integer exponential) {this.exponential = exponential;}  @Overridepublic String toString () {return this.coefficient.toString () + "x^" + this.exponential.toString ();}}

It can also be implemented in maps, and it's easier

Using the Java List to implement polynomial addition, multiply