另类乘法

描述

Bessie is tired of multiplying pairs of numbers the usual way, so she invented her own style of multiplication. In her style, A*B is equal to the sum of all possible pairwise products between the digits of A and B. For example, the product 123*45 is equal to 1*4 + 1*5 + 2*4 + 2*5 + 3*4 + 3*5 = 54. Given two integers A and B (1 ≤ A, B ≤ 1,000,000,000), determine A*B in Bessie‘s style of multiplication.

输入

The first Line of the input is a positive integer T,indicates the number of the test cases;
In every case,the input is in one line,contains two positive interger A,B

输出

For every case,output the multiplication in Bessie‘s style.

样例输入

1
123 45

样例输出

54

package demo1;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int caseNo = input.nextInt();
		for (int i = 1;i<=caseNo;i++) {
			handle(input.nextInt(),input.nextInt());
		}
	}

	private static void handle(int num1, int num2) {
		List<Integer> list1 = getList(num1);
		List<Integer> list2 = getList(num2);
		
		int result = solution(list1,list2);
		System.out.println(result);
		
	}

	private static int solution(List<Integer> list1, List<Integer> list2) {
		int sum = 0;
		if (list1 != null && list1.size()>0) {
			
			for (int i = list1.size()-1;i>=0;i--) {
				int num1 = list1.get(i);
				if (list2 != null && list2.size()>0) {
					for (int j = list2.size()-1;j>=0;j--) {
						int num2 = list2.get(j);
						sum+=num1* num2;
					}
				}
			}
		}
		return sum;
	}

	private static List<Integer> getList(int number) {
		List<Integer> list = new ArrayList<Integer>();
		int temp = 0;
		while (number != 0) {
			temp = number%10;
			list.add(temp);
			number = number/10;
		}
		return list;
	}
	
	public static void display(List<Integer>list){
		if (list != null && list.size() > 0) {
			for (Integer i:list) {
				System.out.print(i+" ");
			}
		}
	}
	
	
}

　　

另类乘法

原文：http://www.cnblogs.com/airycode/p/6591356.html