一元多项式求和（Java链表实现）

package com.polyn_sum;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class Polyn {
 public float coef;//系数
 public int expn;//指数
}

 class LNode {
  Polyn polyn;
  LNode next;
 
  public static String show(LNode p){
   return (p.polyn.coef+","+p.polyn.expn);
  }
 
 
 public static LNode createList(int num) throws IOException {
   LNode head = new LNode();
   LNode p = null;
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   for (int i = 0; i < num; ++i) {
    LNode q = new LNode();
    String[] xx = br.readLine().split(",");
    //System.out.println("xx[0]"+xx[0]+",xx[1]"+xx[1]);
    q.next = null;
    q.polyn = new Polyn();
    q.polyn.coef = Float.valueOf(xx[0]);
    q.polyn.expn = Integer.valueOf(xx[1]);
    if (i == 0) {
     head.next = q;
    } else {
     p.next = q;
    }
    p = q;
   }
   return head;
  }

 /**
  * 比较指数之和
  * @param qa
  * @param qb
  * @return
  */
 public static int cmp(LNode qa, LNode qb){
  if(qa.polyn.expn < qb.polyn.expn)
   return -1;
  else if(qa.polyn.expn == qb.polyn.expn)
   return 0;
  else
   return 1;
 }
}

 

 

package com.polyn_sum;

import java.io.IOException;

public class Sum {

 public static void main(String[] args) {
  try {
   LNode Alist = LNode.createList(3);
   LNode Blist = LNode.createList(4);
   Alist = AddPolyn(Alist, Blist);
   LNode p = Alist.next;
   while(p != null){
    System.out.println(p.polyn.coef+","+p.polyn.expn);
    p = p.next;
   }
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

 /**
  * 多项式相加(ok)
  */
 public static LNode AddPolyn(LNode Alist, LNode Blist) {
  LNode ha = Alist;//头结点
  LNode hb = Blist;//头结点
  LNode qa = Alist.next;//第一项
  LNode qb = Blist.next;//第一项
  
  while (qa!= null && qb != null) {
   System.out.println("当前比较："+LNode.show(qa)+"<>"+LNode.show(qb));
   switch (LNode.cmp(qa, qb)) {
   case -1:
    ha = qa;
    qa = qa.next;
    //System.out.println("qa < qb");
    break;
   case 0:
    float sum = qa.polyn.coef + qb.polyn.coef;//求系数和
    if (sum != 0f) {
     qa.polyn.coef = sum;//不等于0，合并
     ha = qa;
     qa = qa.next;
     //释放qb
     hb.next = qb.next;
     qb = null;
     qb = hb.next;
     //System.out.println("qa + qb != 0");
    } else {
     ha.next = qa.next;// 等于0，删除当前节点
     qa = null;
     qa = ha.next;
     hb.next = qb.next;
     qb = null;
     qb = hb.next;
     //System.out.println("qa + qb = 0");
    }
    break;
   case 1:
    hb.next = qb.next;
    qb.next = ha.next;
    ha.next = qb;
    ha = qb;
    qb = hb.next;
    //System.out.println("qa > qb");
    break;
   }
  }
  
  if(qb != null){
   ha.next = qb;
  }
  
  return Alist;
 }
}