Method random

src/class041/Code03_SameMod.java:10–12

()

	// 为了测试
	public static long random() {
		return (long) (Math.random() * Long.MAX_VALUE);
	}

	// 计算 ((a + b) * (c - d) + (a * c - b * d)) % mod 的非负结果
	public static int f1(long a, long b, long c, long d, int mod) {