题解 | #a+b#

#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
int main()
{
    string a, b, ans;
    while (cin >> a >> b) {
        ans = "";
        reverse(a.begin(), a.end());
        reverse(b.begin(), b.end());
        int len1 = a.size();
        int len2 = b.size();
        int i = 0,carry = 0;
        while (i < len1 && i < len2) {
            int cur = a[i] - '0' + b[i] - '0' + carry;
            ans += to_string(cur % 10);
            carry = cur / 10;
            i++;
        }
        if (i < len2) {
            swap(a, b);
            swap(len1, len2);
        }
        while (i < len1) {
            int cur = a[i] - '0' + carry;
            ans += to_string(cur % 10);
            carry = cur / 10;
            i++;
        }
        if (carry)
            ans += to_string(carry);
        reverse(ans.begin(), ans.end());
        cout << ans << endl;
    }
}