题解 | #高精度整数加法#

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

int main(){
    string s1,s2;
    std::cin >> s1 >> s2;
    int pre=0;
    string res;
    while(!s1.empty() && !s2.empty()){
        int sum = s1.back()-'0'+s2.back()-'0'+pre;
        if(sum > 9){
            pre=1;
        }else{
            pre=0;
        }
        s1.pop_back();s2.pop_back();
        res.push_back('0'+sum%10);
    }
    if(!s1.empty()){
        while(!s1.empty()){
            int sum = s1.back()-'0'+pre;
            if(sum > 9){
                pre=1;
            }else{
                pre=0;
            }
            s1.pop_back();
            res.push_back('0'+sum%10);
        }
    }else if(!s2.empty()){
        while(!s2.empty()){
            int sum = s2.back()-'0'+pre;
            if(sum > 9){
                pre=1;
            }else{
                pre=0;
            }
            s2.pop_back();
            res.push_back('0'+sum%10);
        }
    }

    if(pre){
        res.push_back('1');
    }

    reverse(res.begin(),res.end());
    std::cout << res;
    return 0;
}