題目如下：
Problem D: ShellSort
He made each turtle stand on another one's back
And he piled them all up in a nine-turtle stack.
And then Yertle climbed up. He sat down on the pile.
What a wonderful view! He could see 'most a mile!
The Problem
King Yertle wishes to rearrange his turtle throne to place his highest-ranking nobles and closest advisors nearer to the top. A single operation is available to change the order of the turtles in the stack: a turtle can crawl out of its position in the stack
and climb up over the other turtles to sit on the top.
Given an original ordering of a turtle stack and a required ordering for the same turtle stack, your job is to determine a minimal sequence of operations that rearranges the original stack into the required stack.
The first line of the input consists of a single integer K giving the number of test cases. Each test case consist on an integer n giving the number of turtles in the stack. The next n lines specify the original ordering of the turtle stack. Each of the lines
contains the name of a turtle, starting with the turtle on the top of the stack and working down to the turtle at the bottom of the stack. Turtles have unique names, each of which is a string of no more than eighty characters drawn from a character set consisting
of the alphanumeric characters, the space character and the period (`.'). The next n lines in the input gives the desired ordering of the stack, once again by naming turtles from top to bottom. Each test case consists of exactly 2n+1 lines in total. The number
of turtles (n) will be less than or equal to two hundred.
For each test case, the output consists of a sequence of turtle names, one per line, indicating the order in which turtles are to leave their positions in the stack and crawl to the top. This sequence of operations should transform the original stack into the
required stack and should be as short as possible. If more than one solution of shortest length is possible, any of the solutions may be reported. Print a blank line after each test case.
Sample Input
2
3
Yertle
Duke of Earl
Sir Lancelot
Duke of Earl
Yertle
Sir Lancelot
9
Yertle
Duke of Earl
Sir Lancelot
Elizabeth Windsor
Michael Eisner
Richard M. Nixon
Mr. Rogers
Ford Perfect
Mack
Yertle
Richard M. Nixon
Sir Lancelot
Duke of Earl
Elizabeth Windsor
Michael Eisner
Mr. Rogers
Ford Perfect
Mack
Sample Output
Duke of Earl
Sir Lancelot
Richard M. Nixon
Yertle
這題要求將一堆亂序的烏龜排成題目要求的順序，烏龜只能移到第一個，要求輸出移動的烏龜，並且要求操作最少，自己的老是超時，網上參考了別人的代碼（），發現了該問題的本質，就是從下到上遍歷目標序列，找到第一個在亂序中的下標大於目標序列下標的烏龜，這樣剩下的烏龜只要按照目標序列的順序依次移動即可。找到第一個烏龜的過程中，滿足保序性（姑且這麼說），就是在亂序數組的循環變量只能不斷往下降，所以兩個數組中判斷過的烏龜順序一致，等會兒把第一個烏龜以上的烏龜都移動後這些烏龜一定會對應起來。代碼很簡單。
AC的代碼如下：
