LeetCode——Multiply Strings

来源：互联网发布：js获取来源url 编辑：程序博客网时间：2024/05/16 17:36

Given two numbers represented as strings, return multiplication of the numbers as a string.

Note: The numbers can be arbitrarily large and are non-negative.

原题链接：https://oj.leetcode.com/problems/multiply-strings/

按照乘法原理，从个位开始一位一位相乘相加。

public class MultiplyStrings {public static void main(String[] args) {String ret = new MultiplyStrings().multiply("12","12");System.out.println(ret);}public String multiply(String num1, String num2) {if(num1 == null || num2 == null || num1.length() == 0 || num2.length() == 0)return "";if(num1.charAt(0) == '0' || num2.charAt(0) == '0')return "0";int num = 0;StringBuilder builder = new StringBuilder();for(int i=num1.length() + num2.length();i>0;i--){for(int j=Math.min(i-1,num1.length());j>0;j--){if(i - j <= num2.length())num += (int)(num1.charAt(j-1)-'0') * (int)(num2.charAt(i-1-j)-'0');}if(i != 1 || num >0)builder.append(num%10);num /= 10;}return builder.reverse().toString();}}

0 0