Word Game 的编写实现

Question

Problem Description
It's a game with two players. Given a dictionary of words, a word S chosen from the dictionary to start with, and a word T also chosen from the dictionary as the winning word, which will be described below, the two players take turns to choose a word from the dictionary, satisfying that the first letter of the chosen word is the same as the last letter of previous word. Each word could be chosen more than once.
Suppose they play exactly n rounds. At the last round, if the player (the first one if n is odd, the second one otherwise) chooses the winning word T, he wins. To your surprise that, the two players are not so clever that they choose words randomly.
Here comes the question. How many different ways will the first player win if they play no more than N rounds, among all the possible ways satisfying all the conditions above?

Input
An integer C, indicates the number of test cases.
Then comes C blocks, formatted like this:
An integer M, indicates the number of words in the dictionary, M <= 30.
M string consisting of only lowercase letters, represent the words in the dictionary. The length of each word is no more than 10. There are no duplicated words.
String S, the word to start with.
String T, the winning word.
A positive integer N, indicates the maximum number of rounds to play. N fits in a signed 32-bit integer.

Output
For each test case, print a line with an integer W, indicating how many possible ways the first player wins.
Output the answer modulo 10001.

Sample Input
1
3
abc
cac
cde
abc
cde
3

Sample Output
2

Answer 1

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# 读取数据
input <- readLines()
N <- as.integer(input[1])
words <- input[2:][[1]]
s <- input[3]
t <- input[4]

# 创建一个字典来存储单词
word_dict <- list(words)

# 初始化结果变量
result <- 0

# 遍历每个可能的词对(s,t)
for(word_pair in unique(c(t, s))) {
  # 构建字符串列表
  word_list <- paste0(word_pair, paste0(letters[s], collapse = ""))

  # 检查是否是有效的词对
  if(word_list %in% word_dict) {
    # 更新结果变量
    result <- result + 1
  }
}

# 输出结果
print(result)