题解 | #高精度整数加法#

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


int main() 
{
    string str1,str2;
    while(cin>>str1>>str2)
    {
        int i=str1.size()-1,j=str2.size()-1;
        int carry=0;
        string ans;
        while(0<=i&&0<=j)
        {
            int temp=(str1[i]-'0')+(str2[j]-'0')+carry;
            --i;--j;
            ans.push_back(
                temp%10+'0'
            );
            carry=temp/10;
        }
        while(0<=i)
        {
            int temp=(str1[i]-'0')+carry;
            --i;
            ans.push_back(
                temp%10+'0'
            );
            carry=temp/10;
        }
        while(0<=j)
        {
            int temp=(str2[j]-'0')+carry;
            --j;
            ans.push_back(
                temp%10+'0'
            );
            carry=temp/10;
        }
        if(carry!=0)
        {
            ans.push_back(
                carry+'0'
            );
        }
        reverse(ans.begin(), ans.end());
        cout<<ans<<endl;
    }
    
}
// 64 位输出请用 printf("%lld")