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5557:Matching Compressed String

题目描述
You are given a long string and looking for certain patterns in the string.
The string contains only lowercase letters $(a-z)$, and it is represented in a compressed format. Denoting $S_1, S_2, ...$ as compressed strings, another compressed string $S$ is defined recursively in one of the following ways:

  $\cdot$ $S$ can be any string consisting of only lowercase letters $(a-z)$.
  $\cdot$ $S$ can be generated by repeating another string for any times. Specifically, $S$ is represented as “R(S1)”, which means that the content of $S_1$ is repeated $R$ times.
  $\cdot$ $S$ can also be the concatenation of other strings. Specifically, $S$ is represented as “$S_1,S_2...S_L$”, which means $S$ is the concatenation of $S_1, S_2, ..., S_L$.
  $\cdot$An empty string (“”) is also a valid representation.

Formally, the Backus–Naur Form (BNF) specification of the syntax is

<compressed> ::= “” | <lowercase-letter> | <compressed> <compressed> | <number> “(” <compressed> “)”

For example, the string “baaabbaaab” can be compressed as “b3(a)2(b)3(a)b”. It can also be compressed as “2(b3(a)b)”.

On the other hand, you find deterministic finite automaton (DFA) as powerful way to describe the patterns you are looking for. A DFA contains a finite set of states $Q$ and a finite set of input symbols called the alphabet Σ. Initially, the DFA is positioned at the start state $q_0∈Q$. Given the transition function $δ(q,a)$ and an input symbol $a$, the DFA transit to state $δ(q,a)$ if its current state is $q$.

Let $w=a_1 a_2...a_n$ be a string over the alphabet Σ. According to the above definition, the DFA transits through the following sequence of states.
$$q_0,q_1=δ(q_0,a_1 ),q_2=δ(q_1,a_2 ),…,q_n=δ(q_(n-1),a_n )$$
The DFA also contains a set of accept states $F\subseteq Q$. If the last state $q_n$ is an accept state, we say that the DFA accepts the string $w$. The set of accepted strings is referred as the language that the DFA represents.

Now you are given a compressed string $S$ and a DFA $A$. You want to know if $A$ accepts the decompressed content of $S$.
输入解释
The first line of input contains a number T indicating the number of test cases ($T≤200$).

The first line of each test case contains a non-empty compressed string $S$, as described above. The length of $S$ is not greater than 10000, and $0≤R≤10^9$. It is guaranteed that the representation of $S$ is valid.

The description of the DFA follows.

The first line of the description contains three integers $N$, $M$, and $K$, indicating the number of states, the number of rules describing the transition function, and the number of accept states ($1≤K≤N≤1000,0≤M≤26N$). The states are numbered from 0 to $N-1$. The start state is always 0.

The second line contains $K$ integers representing the accept states. All these numbers are distinct.

Each of the next $M$ lines consists of two states $p$ and $q$, and an input symbol $a$, which means that the DFA transits from $p$ to $q$ when it receives the symbol $a$. The symbol $a$ is always a lowercase letter. It is guaranteed that, given $p$ and $a$, the next state $q$ is unique.
输出解释
For each test case, output a single line consisting of “Case #X: Y”. $X$ is the test case number starting from 1. $Y$ is “Yes” if the DFA accepts the string, or “No” otherwise.
输入样例
3
2(b3(a)b)
2 3 1
0
0 1 b
1 0 b
1 1 a
b3(a)2(b)3(a)b
2 2 1
1
0 1 b
1 0 a
b3(a)2(b)3(a)b
2 4 1
0
0 1 b
0 1 a
1 0 a
1 0 b
输出样例
Case #1: Yes
Case #2: No
Case #3: Yes
来自杭电HDUOJ的附加信息
Recommend wange2014

该题目是Virtual Judge题目,来自 杭电HDUOJ

源链接: HDU-5557

最后修改于 2020-10-25T23:23:44+00:00 由爬虫自动更新

共提交 0

通过率 --%
时间上限 内存上限
12000/6000MS(Java/Others) 65536/65536K(Java/Others)