题解 | #高精度整数加法#

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

string addStrings(string num1, string num2) {
    string result;
    int carry = 0;
    int i = num1.length() - 1;
    int j = num2.length() - 1;
    
    while (i >= 0 || j >= 0 || carry > 0) {
        int sum = carry;
        if (i >= 0) sum += num1[i--] - '0';
        if (j >= 0) sum += num2[j--] - '0';
        
        carry = sum / 10;
        result += (sum % 10 + '0');
    }
    
    reverse(result.begin(), result.end());
    return result;
}

int main() {
    string num1, num2;
    while (cin >> num1 >> num2) {
        cout << addStrings(num1, num2) << endl;
    }
    return 0;
}

import java.util.*;

public class Main {
    public static String addStrings(String num1, String num2) {
        StringBuilder result = new StringBuilder();
        int carry = 0;
        int i = num1.length() - 1;
        int j = num2.length() - 1;
        
        while (i >= 0 || j >= 0 || carry > 0) {
            int sum = carry;
            if (i >= 0) sum += num1.charAt(i--) - '0';
            if (j >= 0) sum += num2.charAt(j--) - '0';
            
            carry = sum / 10;
            result.append(sum % 10);
        }
        
        return result.reverse().toString();
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String num1 = sc.next();
            String num2 = sc.next();
            System.out.println(addStrings(num1, num2));
        }
    }
}

def add_strings(num1: str, num2: str) -> str:
    result = []
    carry = 0
    i, j = len(num1) - 1, len(num2) - 1
    
    while i >= 0 or j >= 0 or carry:
        sum_val = carry
        if i >= 0:
            sum_val += int(num1[i])
            i -= 1
        if j >= 0:
            sum_val += int(num2[j])
            j -= 1
            
        carry = sum_val // 10
        result.append(str(sum_val % 10))
    
    return ''.join(result[::-1])

while True:
    try:
        num1 = input()
        num2 = input()
        print(add_strings(num1, num2))
    except EOFError:
        break