代码功能是输出数字1到n的字典排序结果，代码中的n为4， 代码编写过程参考下面的例子：

初始序列为2763541

第一步2763541找出最后一个正序35

第二步2763541找出3后面比3大的最后一个数，为4

第三步2764531交换3,4的位置

第四步2764135把4后面的531反序排列为135，得到最后的输出。 -Code function is the output of the 1 to the n of the dictionary sort results, the code of the n is 4, the initial 1234

Should the code writing process refer to the following example:

The initial sequence is 2763541

The first step to find the last 2763541 a positive 35

Second step 2763541 to find the last number of 3 behind 3, 4

Third step 2764531 exchange 3,4 location

The 2764135 step fourth to 4 in the back of the order of 531 to 135, get the final output.* /