日度归档：24 2 月, 2017

Openjudge Zipper

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Zipper

总时间限制:
1000ms
内存限制:
65536kB
描述
Given three strings, you are to determine whether the third string can be formed by combining the characters in the first two strings. The first two strings can be mixed arbitrarily, but each must stay in its original order.

For example, consider forming “tcraete” from “cat” and “tree”:

String A: cat
String B: tree
String C: tcraete

As you can see, we can form the third string by alternating characters from the two strings. As a second example, consider forming “catrtee” from “cat” and “tree”:

String A: cat
String B: tree
String C: catrtee

Finally, notice that it is impossible to form “cttaree” from “cat” and “tree”.

输入
The first line of input contains a single positive integer from 1 through 1000. It represents the number of data sets to follow. The processing for each data set is identical. The data sets appear on the following lines, one data set per line.

For each data set, the line of input consists of three strings, separated by a single space. All strings are composed of upper and lower case letters only. The length of the third string is always the sum of the lengths of the first two strings. The first two strings will have lengths between 1 and 200 characters, inclusive.

输出
For each data set, print:

Data set n: yes

if the third string can be formed from the first two, or

Data set n: no

if it cannot. Of course n should be replaced by the data set number. See the sample output below for an example.

样例输入
3
cat tree tcraete
cat tree catrtee
cat tree cttaree
样例输出
Data set 1: yes
Data set 2: yes
Data set 3: no
来源
Pacific Northwest 2004

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Openjudge 拦截导弹 题解

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拦截导弹

总时间限制:
1000ms
内存限制:
65536kB
描述
某国为了防御敌国的导弹袭击，开发出一种导弹拦截系统。但是这种导弹拦截系统有一个缺陷：虽然它的第一发炮弹能够到达任意的高度，但是以后每一发炮弹都不能高于前一发的高度。某天，雷达捕捉到敌国的导弹来袭，并观测到导弹依次飞来的高度，请计算这套系统最多能拦截多少导弹。拦截来袭导弹时，必须按来袭导弹袭击的时间顺序，不允许先拦截后面的导弹，再拦截前面的导弹。
输入
输入有两行，
第一行，输入雷达捕捉到的敌国导弹的数量k（k<=25），
第二行，输入k个正整数，表示k枚导弹的高度，按来袭导弹的袭击时间顺序给出，以空格分隔。
输出
输出只有一行，包含一个整数，表示最多能拦截多少枚导弹。
样例输入
8
300 207 155 300 299 170 158 65
样例输出
6
来源
医学部计算概论2006期末考试题

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数据结构 邓俊辉 PA#1 祖玛(Zuma) 题解

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祖玛(Zuma)

Description

Let’s play the game Zuma!

There are a sequence of beads on a track at the right beginning. All the beads are colored but no three adjacent ones are allowed to be with a same color. You can then insert beads one by one into the sequence. Once three (or more) beads with a same color become adjacent due to an insertion, they will vanish immediately.

Note that it is possible for such a case to happen for more than once for a single insertion. You can’t insert the next bead until all the eliminations have been done.

Given both the initial sequence and the insertion series, you are now asked by the fans to provide a playback tool for replaying their games. In other words, the sequence of beads after all possible eliminations as a result of each insertion should be calculated.

Input

The first line gives the initial bead sequence. Namely, it is a string of capital letters from ‘A’ to ‘Z’, where different letters correspond to beads with different colors.

The second line just consists of a single interger n, i.e., the number of insertions.

The following n lines tell all the insertions in turn. Each contains an integer k and a capital letter Σ, giving the rank and the color of the next bead to be inserted respectively. Specifically, k ranges from 0 to m when there are currently m beads on the track.

Output

n lines of capital letters, i.e., the evolutionary history of the bead sequence.

Specially, “-” stands for an empty sequence.

Example

Input

ACCBA
5
1 B
0 A
2 B
4 C
0 A

Output

ABCCBA
AABCCBA
AABBCCBA
-
A

Restrictions

0 <= n <= 10^4

0 <= length of the initial sequence <= 10^4

Time: 2 sec

Memory: 256 MB

Hints

List

描述

祖玛是一款曾经风靡全球的游戏，其玩法是：在一条轨道上初始排列着若干个彩色珠子，其中任意三个相邻的珠子不会完全同色。此后，你可以发射珠子到轨道上并加入原有序列中。一旦有三个或更多同色的珠子变成相邻，它们就会立即消失。这类消除现象可能会连锁式发生，其间你将暂时不能发射珠子。

开发商最近准备为玩家写一个游戏过程的回放工具。他们已经在游戏内完成了过程记录的功能，而回放功能的实现则委托你来完成。

游戏过程的记录中，首先是轨道上初始的珠子序列，然后是玩家接下来所做的一系列操作。你的任务是，在各次操作之后及时计算出新的珠子序列。

输入

第一行是一个由大写字母’A’~’Z’组成的字符串，表示轨道上初始的珠子序列，不同的字母表示不同的颜色。

第二行是一个数字n，表示整个回放过程共有n次操作。

接下来的n行依次对应于各次操作。每次操作由一个数字k和一个大写字母Σ描述，以空格分隔。其中，Σ为新珠子的颜色。若插入前共有m颗珠子，则k ∈ [0, m]表示新珠子嵌入之后（尚未发生消除之前）在轨道上的位序。

输出

输出共n行，依次给出各次操作（及可能随即发生的消除现象）之后轨道上的珠子序列。

如果轨道上已没有珠子，则以“-”表示。

样例

见英文题面

限制

0 ≤ n ≤ 10^4

0 ≤ 初始珠子数量 ≤ 10^4

时间：2 sec

内存：256 MB

提示

列表

普通字符串模拟即可：

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数据结构 邓俊辉 PA#2 列车调度(Train) 题解

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Description

Figure 1 shows the structure of a station for train dispatching.

Figure 1

In this station, A is the entrance for each train and B is the exit. S is the transfer end. All single tracks are one-way, which means that the train can enter the station from A to S, and pull out from S to B. Note that the overtaking is not allowed. Because the compartments can reside in S, the order that they pull out at B may differ from that they enter at A. However, because of the limited capacity of S, no more that m compartments can reside at S simultaneously.

Assume that a train consist of n compartments labeled {1, 2, …, n}. A dispatcher wants to know whether these compartments can pull out at B in the order of {a1, a2, …, an} (a sequence). If can, in what order he should operate it?

Input

Two lines:

1st line: two integers n and m;

2nd line: n integers separated by spaces, which is a permutation of {1, 2, …, n}. This is a compartment sequence that is to be judged regarding the feasibility.

Output

If the sequence is feasible, output the sequence. “Push” means one compartment goes from A to S, while “pop” means one compartment goes from S to B. Each operation takes up one line.

If the sequence is infeasible, output a “no”.

Example 1

Input

5 2
1 2 3 5 4

Output

push
pop
push
pop
push
pop
push
push
pop
pop

Example 2

Input

5 5
3 1 2 4 5

Output

No

Restrictions

1 <= n <= 1,600,000

0 <= m <= 1,600,000

Time: 2 sec

Memory: 256 MB

描述

某列车调度站的铁道联接结构如Figure 1所示。

其中，A为入口，B为出口，S为中转盲端。所有铁道均为单轨单向式：列车行驶的方向只能是从A到S，再从S到B；另外，不允许超车。因为车厢可在S中驻留，所以它们从B端驶出的次序，可能与从A端驶入的次序不同。不过S的容量有限，同时驻留的车厢不得超过m节。

设某列车由编号依次为{1, 2, …, n}的n节车厢组成。调度员希望知道，按照以上交通规则，这些车厢能否以{a1, a2, …, an}的次序，重新排列后从B端驶出。如果可行，应该以怎样

的次序操作?

输入

共两行。

第一行为两个整数n，m。

第二行为以空格分隔的n个整数，保证为{1, 2, …, n}的一个排列，表示待判断可行性的驶出序列{a1，a2，…，an}。

输出

若驶出序列可行，则输出操作序列，其中push表示车厢从A进入S，pop表示车厢从S进入B，每个操作占一行。

若不可行，则输出No。

样例

见英文题面

限制

1 ≤ n ≤ 1,600,000

0 ≤ m ≤ 1,600,000

时间：2 sec

空间：256 MB

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