java 鏈表實現多項式加法！

<p style="color:rgb(85, 85, 85);">
</p>package pers.mao.test.ACM;

import java.util.Scanner;

class Node {
	int coef;
	int exp;
	Node next;

	public Node(int coef, int exp) {
		this.coef = coef;
		this.exp = exp;
		this.next = null;
	}
}

class PolyLinked {
	public Node frist;
	public Node last;

	public void createNode(int coef, int exp) {
		Node newNode = new Node(coef, exp);
		if (frist == null) {
			frist = newNode;
			last = newNode;
		} else {
			last.next = newNode;
			last =  newNode;
		}
	}
	public int size() {
		Node newNode;
		int i=0;
		if(frist==null)
			return 0;
		if(frist==last)
			return 1;
		newNode=frist;
		if(newNode.next!=last)
			newNode.next=newNode;
			i++;
		return i;
	}
	public void printPolyList() {
		Node current = frist;
		StringBuilder print = new StringBuilder(""); //用於顯示錶達式；
		while (current != null) {
			if (current.coef != 0 && current.exp == 1) {   
				
				//指數爲1，StringBuilder中有數據，若係數爲負數則刪除之前的加號（注意加號前後都需空格），再追加新的數據；
				if (current.coef < 0 && print.length() >= 2)    
					print.delete(print.length() - 2, print.length() - 1);
				//指數爲1，若係數爲1則不顯示係數；
				if (current.coef == 1) {
					print.append("X + ");
				}else {
					print.append(current.coef + "X + ");
				}
			} else if (current.coef != 0 && current.exp == 0) {  //指數爲0,即常數項；
				//指數爲0，StringBuilder中有數據，若係數爲負數則刪除之前的加號（注意加號前後都需空格），再追加新的數據；
				if (current.coef < 0 && print.length() >= 2)     
					print.delete(print.length() - 2, print.length() - 1);
				print.append(current.coef);
			} else if (current.coef != 0 && current.exp != 0) { //指數大於1；
				//StringBuilder中有數據，若係數爲負數則刪除之前的加號（注意加號前後都需空格），再追加新的數據；
				if (current.coef < 0 && print.length() >= 2)
					print.delete(print.length() - 2, print.length() - 1);
				if (current.coef == 1) {   
					print.append( "X^" + current.exp + " + ");
				} else if (current.coef == -1) {
					print.append("-"+"X^" + current.exp + " + ");
				}
				else {
					print.append(current.coef + "X^" + current.exp + " + ");
				}
			}
			current = current.next;
		}
		if (last.coef == 0)
			print.delete(print.length() - 2, print.length() - 1);
		System.out.print(print.toString());
	}

	public PolyLinked Polyadd(PolyLinked b) {
		int max = Math.max(this.frist.exp, b.frist.exp);
		int i = 0;
		int[][] sum = new int[max + 1][2];
		PolyLinked tem = new PolyLinked();
		PolyLinked a = new PolyLinked();
		a = this;
		while (a.frist != null && b.frist != null) {
			if (a.frist.exp == b.frist.exp) {
				sum[i][0] = a.frist.coef + b.frist.coef;
				sum[i][1] = a.frist.exp;
				a.frist = a.frist.next;
				b.frist = b.frist.next;
				i++;
			} else if (a.frist.exp > b.frist.exp) {
				sum[i][0] = a.frist.coef;
				sum[i][1] = a.frist.exp;
				a.frist = a.frist.next;
				i++;
			} else if (b.frist.exp > a.frist.exp) {
				sum[i][0] = b.frist.coef;
				sum[i][1] = b.frist.exp;
				b.frist = b.frist.next;
				i++;
			}
		}
		while (a.frist != null) {
			sum[i][0] = a.frist.coef;
			sum[i][1] = a.frist.exp;
			a.frist = a.frist.next;
			i++;
		}
		while (b.frist != null) {
			sum[i][0] = b.frist.coef;
			sum[i][1] = b.frist.exp;
			b.frist = b.frist.next;
			i++;
		}
		int maxnuber = i - 1;
		for (int j = 0; j < maxnuber + 1; j++) {
			tem.createNode(sum[j][0], sum[j][1]);
		}
		return tem;
	}
	
}

public class PolyLinkedAdd {

	public static void main(String[] args) {
		int[] coef = new int[10];
		int[] exp = new int[10];
		PolyLinked a = new PolyLinked();
		PolyLinked b = new PolyLinked();
		PolyLinked c = new PolyLinked();

		Scanner scan = new Scanner(System.in); // 接收鍵盤的輸入
		String str = scan.nextLine();
		int line = 0;
		while (!str.equals(" ")) {
			String[] num = str.split(" ");
			coef[line] = Integer.parseInt(num[0]);
			exp[line] = Integer.valueOf(num[1]);
			line++;
			str = scan.nextLine();
		}
		scan.close();
		/* flag 用於存儲輸入的0 和-1的位置，以便將兩組數據分開 */
		int flag[] = new int[2];
		int ii = 0;
		for (int j = 0; j < line; j++) {
			if (coef[j] == 0 && exp[j] == -1) {
				flag[ii] = j;
				ii++;
			}
		}
		/*
		 * data用於存儲兩個多項式的各項係數，長度分別爲各多項式的最高項加1
		 * flag[0]爲exp[]中，第一次出現0，-1的位置，所以加1就表示第二組多項式的第一個元素
		 */
		int[] data1 = new int[exp[0] + 1];
		int[] data2 = new int[exp[flag[0] + 1] + 1];

		/* 前兩個for循環，先給多項式的所有係數，初始化爲0，後兩個for循環再爲非零項賦值 */
		for (int k = 0; k < data1.length; k++) {
			data1[k] = 0;
		}
		for (int k = 0; k < data2.length; k++) {
			data2[k] = 0;
		}

		for (int k = 0; k < flag[0]; k++) {
			data1[data1.length - 1 - exp[k]] = coef[k];
		}
		for (int k = flag[0] + 1; k < flag[1]; k++) {
			data2[data2.length - 1 - exp[k]] = coef[k];
		}

		/* 輸出顯示各多項式！ */
		System.out.print("原多項式： \nA=");
		for (int i = 0; i < data1.length; i++)
			a.createNode(data1[i], data1.length - i - 1);
		for (int i = 0; i < data2.length; i++)
			b.createNode(data2[i], data2.length - i - 1);
		a.printPolyList();
		System.out.print("\nB=");
		b.printPolyList();
		System.out.print("\n多項式相加的結果： \nC=");
		c = a.Polyadd(b);
		c.printPolyList();

	}
}