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！！！