B. Jzzhu and Sequences

http://codeforces.com/contest/450/problem/B

 

这个数列是循环数列

    public static void main(String[] args) {
        IO io = new IO();
        long a = io.nextInt(), b = io.nextInt(), n = io.nextInt();
        long[] ans = new long[]{a, b, b - a, -a, -b, a - b};
        long res = ans[(int) ((n - 1) % 6)];
        while (res<0)res+=M;
        io.println(res%M);
    }