藍橋杯多項式相乘

題目鏈接

思路：

直接按多項式相乘的方法進行模擬。
我們巧妙的運用一個數組arr
則有arr[q項數 + h項數 ] = (q係數 * h係數);
這樣一來最後倒序輸出即可。

優化後代碼

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]);
			}
			
	}
}