题解 | #高精度整数加法#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String a = in.nextLine();
        String b = in.nextLine();
        int i=a.length()-1, j=b.length()-1;
        StringBuilder sb = new StringBuilder();
        int bit = 0;
        while(i>=0 && j>=0) {
            int num1 = a.charAt(i)-'0';
            int num2 = b.charAt(j)-'0';
            int sum = num1 + num2 + bit;
            if(sum>=10) {
                sum-=10;
                bit = 1;
            } else {
                bit = 0;
            }
            i--;
            j--;
            sb.append(sum);
        }
        while(i>=0) {
            int num1 = a.charAt(i)-'0';
            int sum = num1 + bit;
            if(sum>=10) {
                sum-=10;
                bit = 1;
            } else {
                bit = 0;
            }
            i--;
            sb.append(sum);
        }
        while(j>=0) {
            int num1 = b.charAt(j)-'0';
            int sum = num1 + bit;
            if(sum>=10) {
                sum-=10;
                bit = 1;
            } else {
                bit = 0;
            }
            j--;
            sb.append(sum);
        }
        if(bit>0) {
            sb.append(bit);
        }
        System.out.println(sb.reverse().toString());
    }
}