C++实现

#include<iostream>
#include<vector>
using namespace std;


vector<int> add(vector<int> &a, vector<int> &b){
    vector<int> ans;
    int t = 0;
    for(int i = 0; i < a.size() || i < b.size(); i++){
        if(i < a.size()) t += a[i];
        if(i < b.size()) t += b[i];
        ans.push_back(t%10);
        t /= 10;
    }
    if(t) ans.push_back(t);
    return ans;
}

int main(){
    string a, b;
    vector<int>A, B;
    cin >> a >> b;
    for(int i = a.size()-1; i >= 0; i--) A.push_back(a[i]-'0');
    for(int i = b.size()-1; i >= 0; i--) B.push_back(b[i]-'0');
    auto C = add(A,B);
    for(int i = C.size()-1; i >= 0; i--) printf("%d", C[i]);
    return 0;
}

Java实现

import java.io.*;
import java.math.BigInteger;
class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader cin = new BufferedReader(new InputStreamReader(System.in));
        String[] s = cin.readLine().split(" ");
        BigInteger n = new BigInteger(s[0]);
        s = cin.readLine().split(" ");
        BigInteger m = new BigInteger(s[0]);
        System.out.println(m.add(n));
    }
}