1 /****************************************************
 2 PAT B1048 数字加密
 3 ****************************************************/
 4 #include <iostream>
 5 #include <string.h>
 6 
 7 using namespace std;
 8 
 9 const char MOD_RESOULT[] = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘J‘, ‘Q‘, ‘K‘ };
10 
11 int main() {
12     string key, num;
13 
14     cin >> key >> num;
15 
16     string ans = num.size() >= key.size() ? num : key;        //此处仅仅是为了让ans的长度等于key与num中最长的
17 
18     for (int i = 0; i < num.size() || i < key.size(); ++i) {
19         //如果出现key和num长度不同的情况需要给较短的那个补‘0’
20         char numInKey = i >= key.size() ? ‘0‘ : key[key.size() - 1 - i];
21         char numInNum = i >= num.size() ? ‘0‘ : num[num.size() - 1 - i];
22 
23         if (i % 2 == 0) {
24             ans[ans.size() - 1 - i] = MOD_RESOULT[(numInKey + numInNum - 2 * ‘0‘) % 13];
25         }
26         else {
27             int n = numInNum - numInKey;
28             ans[ans.size() - 1 - i] = n < 0 ? MOD_RESOULT[n + 10] : MOD_RESOULT[n];
29         }
30     }
31 
32     cout << ans;
33 
34     return 0;
35 }