[开发测试]1002 A+B for Polynomials (25 point(s))

1002 A+B for Polynomials (25 point(s))

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:
…
每个输入文件包含一个测试用例。 每个案例占用2行，并且每行包含一个多项式的信息：
…
where K is the number of nonzero terms in the polynomial, N i N_iN
…
i(i=1,2,?,K) are the exponents and coefficients, respectively. It is given that …

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

Java实现 代码如下：

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Scanner;

/**
 * @author Teletele
 * @desc pta1002题
 * @date 2021-07-07 22:04:46
 */
public class ABPolynomials {
    public static void main(String[] args) {
        //输入部分处理
        Scanner sc = new Scanner(System.in);
        int k1 = sc.nextInt();
        int [] p1_exp=new int[k1];
        double [] p1_coe=new double[k1];
        for(int i=0;i<k1;i++){
            p1_exp[i]=sc.nextInt();
            p1_coe[i]=sc.nextDouble();
        }
        int k2 = sc.nextInt();
        int[] p2_exp = new int[k2];
        double[] p2_coe = new double[k2];
        for (int i =0; i<k2;i++){
            p2_exp[i]=sc.nextInt();
            p2_coe[i]= sc.nextDouble();
        }
        sc.close();

        //多项式加法运算
        ArrayList<Integer> res_exp= new ArrayList<>();  //存储结果的指数信息
        ArrayList<Double>   res_coe = new ArrayList<>();  //存储结果的系数信息
        DecimalFormat changeFormat = new DecimalFormat("0.0");  //修改格式信息

        int i=k1-1,j=k2-1;  //定义两个指针分别指向指数最低的项
        while(i>=0&&j>=0){
            //三种情况该如何处理
            if(p1_exp[i]>p2_exp[j]){
                res_exp.add(p2_exp[j] );
                res_coe.add(p2_coe[j]);
                j--;
            }else  if(p1_exp[i]<p2_exp[j]){
                res_exp.add(p1_exp[i]);
                res_coe.add(p1_coe[i]);
                i--;
            }else{
                //指数相等时进行多项式计算
                if((p1_coe[i]+p2_coe[j])!=0){  //若不为0，则添加多项式
                    res_exp.add(p1_exp[i]);
                    res_coe.add(p1_coe[i]+p2_coe[j]);
                }
                i--;
                j--;
            }
        }
        //循环走完还有其他的项？
        while (i>=0){
            res_exp.add(p1_exp[i]);
            res_coe.add(p1_coe[i]);
            i--;
        }
        while (j>=0){
            res_exp.add(p2_exp[j] );
            res_coe.add(p2_coe[j]);
            j--;
        }

        //结果格式化输出，由于是逆序，这里逆序输出
        int k=res_coe.size();
        System.out.print(k);
        for (int l = k-1; l >=0 ; l--) {
            System.out.print(" "+res_exp.get(l));
            System.out.print(" "+changeFormat.format(res_coe.get(l)));
        }

    }

}