Java实现 洛谷 P1914 小书童——密码

import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String s = sc.next();
		char c;
		for (int j = 0; j < s.length(); j++) {
			// 注意往后移超过一个a-z区间的情况
			c = (char) (s.charAt(j) + n);
			if (c > 'z') {
				char a = (char) ('a' + c % 'z' - 1);
				System.out.print(a);
			} else {
				System.out.print(c);
			}

		}
	}
}