华为机试-超长正整数相加

题目描述
请设计一个算法完成两个超长正整数的加法。

接口说明

/*
请设计一个算法完成两个超长正整数的加法。
输入参数：
String addend：加数
String augend：被加数
返回值：加法结果
*/
public String AddLongInteger(String addend, String augend)
{
/*在这里实现功能*/

return null;
}

输入描述:
输入两个字符串数字

输出描述:
输出相加后的结果，string型

输入例子:
99999999999999999999999999999999999999999999999999
1

输出例子:
100000000000000000000000000000000000000000000000000

Java程序实现

import java.util.Scanner;

/**
 * 超长正整数相加
 *
 * @author LiJian
 *
 */
public class Main {
    @SuppressWarnings("resource")
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        String str1 = "";
        String str2 = "";
        while (sc.hasNextLine()) {
            str1 = sc.nextLine();
            str2 = sc.nextLine();
            String sResult = AddLongInteger(str1, str2);
            System.out.println(sResult);
        }
    }

    public static String AddLongInteger(String str1, String str2) {
        if (str1.length() < str2.length()) {
            String temp = str1;
            str1 = str2;
            str2 = temp;

        }
        char[] charArr1 = str1.toCharArray();
        char[] charArr2 = str2.toCharArray();
        int jinWei = 0;
        int sum = 0;
        for (int i = charArr1.length - 1, j = charArr2.length - 1; i >= 0; i--) {
            if (j >= 0) {
                sum = Integer.parseInt(charArr1[i] + "") + Integer.parseInt(charArr2[j] + "") + jinWei;
                charArr1[i] = String.valueOf(sum % 10).charAt(0);
                jinWei = sum / 10;
                j--;
            } else {
                sum = Integer.parseInt(charArr1[i] + "") + jinWei;
                charArr1[i] = String.valueOf(sum % 10).charAt(0);
                jinWei = sum / 10;
            }
        }
        String value = "";
        for (int i = 0; i < charArr1.length; i++) {
            value += charArr1[i];
        }
        if (jinWei != 0) {
            return String.valueOf(jinWei) + value;
        } else {
            return value;
        }

    }

}