多项式求和，PAT1002

1002 A+B for Polynomials（25 分）

This time, you are supposed to find A+B where A and B are two polynomials.

Input Specification:

Each input file contains one test case. Each case occupies 2 lines, and each line contains the information of a polynomial:

K N1 aN1 N2 aN2 … NK aNK

where K is the number of nonzero terms in the polynomial, Ni and aNi (i=1,2,⋯,K) are the exponents and coefficients, respectively.

Output Specification:

For each test case you should output the sum of A and B in one line, with the same format as the input. Notice that there must be NO extra space at the end of each line. Please be accurate to 1 decimal place.

Sample Input:

2 1 2.4 0 3.2
2 2 1.5 1 0.5

Sample Output:

3 2 1.5 1 2.9 0 3.2

多项式求和

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Answer

• 链表实现

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Collections;
/**
 * Created by Boolean on 2018/8/8.
 */
public class Main {
    public static void main(String[] args)
    {
       Scanner scanner = new Scanner(System.in);
       LinkedList<Node> list = new LinkedList<Node>();
       LinkedList<Node> list1 = new LinkedList<Node>();
       int count = 2;
       while(count>0)
       {
           int n = scanner.nextInt();
           Node node = null;
           while (n>0)
           {
               n--;
               int Exponents = scanner.nextInt();
               double Coefficients = scanner.nextDouble();
               if(Coefficients!=0)
               {
                   node = new Node(Exponents,Coefficients);
                   if(count==2)
                       list.add(node);
                   else list1.add(node);
               }
           }
           count--;
       }
       count = 0;
       int i = 0,j = 0;
       LinkedList<Node> res = new LinkedList<>();
       while (i<list.size()&&j<list1.size())
       {
          // System.out.printf("%d %d\n",i,j);
           Node node1 = list.get(i);
           Node node2 = list1.get(j);
           int ex;double co;
           if(node1.exponents==node2.exponents)
           {
               ex = node1.exponents;
               co = node1.coefficients+node2.coefficients;
               Node newNode = new Node(ex,co);
               res.add(newNode);
               i++;j++;
               if(newNode.coefficients!=0)count++;
           }
           else if(node1.exponents>node2.exponents)
           {
               res.add(node1);i++; count++;
           }
           else
           {
               res.add(node2);j++; count++;
           }
       }
       // System.out.printf("%d %d\n",i,j);
       while (i<list.size())
       {
           Node node = list.get(i);
           i++;
           res.add(node);
           if(node.coefficients!=0)count++;
       }
       while (j<list1.size())
       {
          // System.out.println(j);
           Node node = list1.get(j);
           j++;
           res.add(node);
           if(node.coefficients!=0)count++;
       }
        System.out.printf("%d",count);
        for (Node node:res) {
            if(node.coefficients!=0.0)
                System.out.printf(" %d %.1f",node.exponents,node.coefficients);
        }
    }
    static class Node{
        private int exponents;
        private double coefficients;
        public Node(int exponents,double coefficients)
        {
            this.exponents = exponents;
            this.coefficients = coefficients;
        }
        public int getExponents() {
            return exponents;
        }

        public void setExponents(int exponents) {
            this.exponents = exponents;
        }

        public double getCoefficients() {
            return coefficients;
        }

        public void setCoefficients(double coefficients) {
            this.coefficients = coefficients;
        }
    }
}

• 数组散列实现

import java.util.*;

/**
 * Created by Boolean on 2018/8/8.
 */
public class Main {
    public static void main(String[] args)
    {
       Scanner scanner = new Scanner(System.in);
       int n =scanner.nextInt();
       double[] res = new double[1001];
       int[] list = new int[1001];
       int count = 0;
       while (n>0)
       {
           int ex = scanner.nextInt();
           double coe = scanner.nextDouble();
           res[ex] = coe;
           list[count] = ex;
           count++;
           n--;
       }
       n = scanner.nextInt();
       while (n>0)
       {
           int ex = scanner.nextInt();
           double coe = scanner.nextDouble();
           if(res[ex]==0)
           {
               list[count] = ex;
              // System.out.println(ex);
               count++;
           }
           res[ex] = coe+res[ex];
           n--;
       }
       // System.out.println();
        Arrays.sort(list,0,count);
        int res_c = 0;
        for(int i=0;i<count;i++)
        {
            if(res[list[i]]!=0)
            {
                res_c++;
            }
        }
        System.out.printf("%d",res_c);
        for(int i=count-1;i>=0;i--)
        {
            //System.out.println(list[i]);
            //
           if(res[list[i]]!=0)System.out.printf(" %d %.1f",list[i],res[list[i]]);
        }
    }

}