Java 面试 有1，2，3，4个数字，能组成多少个互不相通且无重复的三位数？都是多少？

    private void test() {
        int number = 0;
        int count = 0;
        for (int i = 1; i <= 4; i++) {
            for (int m = 1; m <= 4; m++) {
                for (int n = 1; n <= 4; n++) {
                    if (i != m && m != n && i != n) {
                        number = i + m * 10 + n * 100;
                        count++;
                        System.out.print(",number==== " + number);
                    }
                }
            }
        }
        System.out.println("count==== " + count);
    }

number==== 321,number==== 421,number==== 231,number==== 431,number==== 241,number==== 341,
number==== 312,number==== 412,number==== 132,number==== 432,number==== 142,number==== 342,
number==== 213,number==== 413,number==== 123,number==== 423,number==== 143,number==== 243,
number==== 214,number==== 314,number==== 124,number==== 324,number==== 134,number==== 234
count==== 24 //调整了格式