题目传送门

#include <iostream>
#include <algorithm>
using namespace std;
int main() 
{
	string a, b, c;
	cin >> a >> b;
	int lena = a.length(), lenb = b.length();
	reverse(a.begin(), a.end());
	reverse(b.begin(), b.end());
	if (lena > lenb)
	{
		b.append(lena - lenb, '0');
	}
	else
	{
		a.append(lenb - lena, '0');
	}
	char str[14] = { "0123456789JQK" };
	for (int i = 0; i < a.length(); i++) 
	{
		if (i % 2 == 0) 
		{
			c += str[(a[i] - '0' + b[i] - '0') % 13];
		}
		else 
		{
			int t = b[i] - a[i];
			if (t < 0) 
			{
				t = t + 10;
			}
			c += str[temp];
		}
	}
	for (int i = c.length() - 1; i >= 0; i--)
	{
		cout << c[i];
	}
	return 0;
}