2019/02/16 STL容器 ：栈

一、栈（stack)

1.定义：
栈是一种只能在某一端插入和删除数据的特殊线性表。他按照先进先出的原则存储数据，先进的数据被压入栈底，最后进入的数据在栈顶，需要读数据的时候从栈顶开始弹出数据(最后被压入栈的，最先弹出）。因此栈也称先进后出表。
允许进行插入删除操作的一端称为栈顶，另一端称为栈底。栈底固定，栈顶浮动。插入元素称为进栈，删除一个元素称为进栈，栈内元素为零称为空栈。
2.stack成员函数
bool empty ( ) ————>栈为空返回true，否则返回false；
void pop （ ) ————>删除栈顶元素，出栈；
void push（const TYPE&value）————> 插入新元素value，放置在栈顶进栈；TYPE：类型int，char…；
size_type size ( ) ————> 返回堆栈中元素个数；（注意注意！！！！切不可赋值给int ，很容易超过int的范围
TYPE&top（）————> 查看当前栈顶元素；

Many areas of Computer Science use simple, abstract domains for both
analytical and empirical studies. For example, an early AI study of
planning and robotics (STRIPS) used a block world in which a robot arm
performed tasks involving the manipulation of blocks.

In this problem you will model a simple block world under certain
rules and constraints. Rather than determine how to achieve a
specified state, you will “program” a robotic arm to respond to a
limited set of commands.

The problem is to parse a series of commands that instruct a robot arm
in how to manipulate blocks that lie on a flat table. Initially there
are n blocks on the table (numbered from 0 to n − 1) with block bi
adjacent to block bi+1 for all 0 ≤ i < n − 1 as shown in the diagram
below:

Initial Blocks World

The valid commands for the robot arm that manipulates blocks are:

• move a onto b

where a and b are block numbers, puts block a onto block b after
returning any blocks that are stacked on top of blocks a and b to
their initial positions.

• move a over b

where a and b are block numbers, puts block a onto the top of the
stack containing block b, after returning any blocks that are stacked
on top of block a to their initial positions.

• pile a onto b

where a and b are block numbers, moves the pile of blocks consisting
of block a, and any blocks that are stacked above block a, onto block
b. All blocks on top of block b are moved to their initial positions
prior to the pile taking place. The blocks stacked above block a
retain their order when moved.

• pile a over b

where a and b are block numbers, puts the pile of blocks consisting of
block a, and any blocks that are stacked above block a, onto the top
of the stack containing block b. The blocks stacked above block a
retain their original order when moved.

• quit

terminates manipulations in the block world. Any command in which a =
b or in which a and b are in the same stack of blocks is an illegal
command. All illegal commands should be ignored and should have no
affect on the configuration of blocks.

Input

The input begins with an integer n on a line by itself representing
the number of blocks in the block world. You may assume that 0 < n <
25.

The number of blocks is followed by a sequence of block commands, one
command per line. Your program should process all commands until the
quit command is encountered. You may assume that all commands will be
of the form specified above. There will be no syntactically incorrect
commands.

Output

The output should consist of the final state of the blocks world. Each
original block position numbered i (0 ≤ i < n where n is the number of
blocks) should appear followed immediately by a colon. If there is at
least a block on it, the colon must be followed by one space, followed
by a list of blocks that appear stacked in that position with each
block number separated from other block numbers by a space. Don’t put
any trailing spaces on a line.

There should be one line of output for each block position (i.e., n
lines of output where n is the integer on the first line of input).

Sample Input

10

move 9 onto 1

move 8 over 1

move 7 over 1

move 6 over 1

pile 8 over 6

pile 8 over 5

move 2 over 1

move 4 over 9

quit

Sample Output

0: 0

1: 1 9 2 4

2:

3: 3

4:

5: 5 8 7 6

6:

7:

8:

9:

本以为这个题要用到stack，结果发现这个题Vector就能做！！！