蓝桥杯多项式相乘

​​题目链接​​

思路：

直接按多项式相乘的方法进行模拟。
我们巧妙的运用一个数组arr
则有arr[q项数 + h项数 ] = (q系数 * h系数);
这样一来最后倒序输出即可。

优化后代码

import java.math.BigInteger;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    int q[][] = new int[2][2];
    int h[][] = new int[2][2];
    int arr[] = new int[24];
    Scanner cin = new Scanner(System.in);
    for (int i = 0; i < 2; i++) {
      for (int j = 0; j < 2; j++) {
        q[i][j] = cin.nextInt();
      }
    }

    for (int i = 0; i < 2; i++) {
      for (int j = 0; j < 2; j++) {
        h[i][j] = cin.nextInt();
      }
    }
    
    for(int i = 0;i < 2;i++) {
      for(int j = 0;j < 2;j++) {
      
        arr[q[i][1] + h[j][1]] += q[i][0] * h[j][0]; 
        
      }
    }
    for(int i = 20;i >= 0;i--) {
      if(arr[i] != 0)System.out.println(arr[i] + " " + i);
    }

  }
}

import java.math.BigInteger;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    int a[] = new int[4];
    int b[] = new int[4];
    int a1[] = new int[4];
    int b1[] = new int[4];
    Scanner cin = new Scanner(System.in);
    for(int i  = 0;i < 4;i++) {
      a[i] = cin.nextInt();
      b[i] = cin.nextInt();
    }
      a1[0] = a[0] * a[2];
      a1[1] = a[0] * a[3];
      a1[2] = a[1] * a[2];
      a1[3] = a[1] * a[3];
      b1[0] = b[0] + b[2];
      b1[1] = b[0] + b[3];
      b1[2] = b[1] + b[2];
      b1[3] = b[1] + b[3];
      int vis[] = new int[5];
      for(int i = 0;i < 4;i++) {
        if(vis[i] == 1)continue;
        for(int j = i + 1;j < 4;j++) {
          if(b1[i] == b1[j]) {
            a1[i] += a1[j];
            a1[j] = 0;
            vis[j] = 1;
          }
        }
      }
      int cnt = 0;
      int t[][] = new int[4][2];
      for(int i  = 0;i < 4;i++) {
        if(a1[i] != 0) {
          t[cnt][0] = a1[i];
          t[cnt][1] = b1[i];
          cnt++;
          
        }
      }
      Arrays.sort(t, 0, cnt, new Comparator<int[]>() {

        @Override
        public int compare(int[] o1, int[] o2) {
          // TODO Auto-generated method stub
          return o2[1] - o1[1];
        }
        
      });
      for(int i = 0;i < cnt;i++) {
        System.out.println(t[i][0] + " " + t[i][1]);
      }
      
  }
}