P1914 小书童——凯撒密码

题目传送门

#include 

using namespace std;

int n;
string s;

int main() {
    cin >> n >> s;
    for (int i = 0; i < s.size(); i++) {
        int c = s[i] + n;
        if (c > 'z') c = c - 'z' - 1 + 'a';
        s[i] = char(c);
    }
    cout << s << endl;
    return 0;
}