IB Java Developer 线上面试

Q6

/**
 * 打印32位和64位无符号数
 *
 */
@Test
public void test3() {
    BigInteger bigInteger = new BigInteger("2");
    int ind = 0;
    int index = 63;
    for(int i = 0; i < index; i++) {
        ind = i + 2;
        bigInteger = bigInteger.multiply(new BigInteger("2"));
        System.out.println(ind + " : " + bigInteger);
    }
}

/**
 * 问：如果遍历 32 位无符号数需要 1 毫秒，那遍历 64 位无符号数需要多长时间？
 * 答：7 周
 */
@Test
public void test4() {
    BigInteger bigInteger64 = new BigInteger("18446744073709551616");
    BigInteger bigInteger32 = new BigInteger("4294967296");
    BigInteger bigIntegerResult = bigInteger64.divide(bigInteger32);
    // 秒
    bigIntegerResult = bigIntegerResult.divide(new BigInteger("1000"));
    // 小时
    bigIntegerResult = bigIntegerResult.divide(new BigInteger("3600"));
    // 天
    bigIntegerResult = bigIntegerResult.divide(new BigInteger("24"));
    // 周
    bigIntegerResult = bigIntegerResult.divide(new BigInteger("7"));
    System.out.println("耗时：" + bigIntegerResult + " 周");
}

Q5

/**
 * 问：运行完成后，x的值为多少？
 * 答： 34
 */
@Test
public void test5() {
    int x = 1;
    int y = 1;
    int z = 1000;
    while (x < 25) {
        z = x;
        x = x + y;
        y = z;
    }
    System.out.println(x);
}