mooc课程mit 6.00.1x--problem set3解决方法

• RADIATION EXPOSURE
  挺简单的一道题，计算函数和算法过程都已经给出，做一个迭代计算就行了。

   def radiationExposure(start, stop, step):
       '''
       Computes and returns the amount of radiation exposed
       to between the start and stop times. Calls the
       function f (defined for you in the grading script)
       to obtain the value of the function at any point.
  
       start: integer, the time at which exposure begins
       stop: integer, the time at which exposure ends
       step: float, the width of each rectangle. You can assume that
         the step size will always partition the space evenly.
  
       returns: float, the amount of radiation exposed to
         between start and stop times.
       '''
       # FILL IN YOUR CODE HERE...
       area = 0
       while start <  stop:
           area = area + f(start) * step
           start += step
  
       return area

• A WORDGAME: HANGMAN
  一个猜单词游戏，个人感觉略有难度，游戏规则见这里。将其分步实现相应的函数。

   # 6.00 Problem Set 3
   #
   # Hangman game
   #
  
   # -----------------------------------
   # Helper code
   # You don't need to understand this helper code,
   # but you will have to know how to use the functions
   # (so be sure to read the docstrings!)
  
   import random
   import string
  
   WORDLIST_FILENAME = "words.txt"
  
   def loadWords():
       """
       Returns a list of valid words. Words are strings of lowercase letters.
  
       Depending on the size of the word list, this function may
       take a while to finish.
       """
       print "Loading word list from file..."
       # inFile: file
       inFile = open(WORDLIST_FILENAME, 'r', 0)
       # line: string
       line = inFile.readline()
       # wordlist: list of strings
       wordlist = string.split(line)
       print "  ", len(wordlist), "words loaded."
       return wordlist
  
   def chooseWord(wordlist):
       """
       wordlist (list): list of words (strings)
       Returns a word from wordlist at random
       """
       return random.choice(wordlist)
  
   # end of helper code
   # -----------------------------------
  
   # Load the list of words into the variable wordlist
   # so that it can be accessed from anywhere in the program
   wordlist = loadWords()
  
   def isWordGuessed(secretWord, lettersGuessed):
       '''
       secretWord: string, the word the user is guessing
       lettersGuessed: list, what letters have been guessed so far
       returns: boolean, True if all the letters of secretWord are in
           lettersGuessed; False otherwise
       '''
       # FILL IN YOUR CODE HERE...
       for c in secretWord:
           if c not in lettersGuessed:
               return False
  
       return True
  
   def getGuessedWord(secretWord, lettersGuessed):
       '''
       secretWord: string, the word the user is guessing
       lettersGuessed: list, what letters have been guessed so far
       returns: string, comprised of letters and underscores that represents
         what letters in secretWord have been guessed so far.
       '''
       # FILL IN YOUR CODE HERE...
       guess = ""
       for c in secretWord:
           if c in lettersGuessed:
               guess += c
           else:
               guess += "_ "
  
       return guess
  
   def getAvailableLetters(lettersGuessed):
       '''
       lettersGuessed: list, what letters have been guessed so far
       returns: string, comprised of letters that represents what letters have not
         yet been guessed.
       '''
       # FILL IN YOUR CODE HERE...
       available = ""
       for c in string.ascii_lowercase:
           if c not in lettersGuessed:
               available += c
  
       return available
  
   def hangman(secretWord):
       '''
       secretWord: string, the secret word to guess.
       Starts up an interactive game of Hangman.
       * At the start of the game, let the user know how many
         letters the secretWord contains.
       * Ask the user to supply one guess (i.e. letter) per round.
       * The user should receive feedback immediately after each guess
         about whether their guess appears in the computers word.
       * After each round, you should also display to the user the
         partially guessed word so far, as well as letters that the
         user has not yet guessed.
       Follows the other limitations detailed in the problem write-up.
       '''
       # FILL IN YOUR CODE HERE...
       print "Welcome to the game Hangman!"
       print "I am thinking of a word that is", len(secretWord), "letters long."
       print "-------------"
       lettersGuessed = []
       mistakesMade = 0
       availableLetters = string.ascii_lowercase
  
       while mistakesMade < 8 and not isWordGuessed(secretWord, lettersGuessed):
           print "You have", 8 - mistakesMade, "guesses left."
           print "Available letters:", availableLetters
           guess = raw_input("Please guess a letter: ").lower()
  
           if guess in lettersGuessed:
               print("Oops! You've already guessed that letter: " +
                   getGuessedWord(secretWord, lettersGuessed))
           elif guess in secretWord:
               lettersGuessed.append(guess)
               print "Good guess:", getGuessedWord(secretWord, lettersGuessed)
           else:
               mistakesMade += 1
               lettersGuessed.append(guess)
               print("Oops! That letter is not in my word: " +
                   getGuessedWord(secretWord, lettersGuessed))
  
           availableLetters = getAvailableLetters(lettersGuessed)
  
           print "------------"
  
       if isWordGuessed(secretWord, lettersGuessed):
           print "Congratulations, you won!"
       else:
           print("Sorry, you ran out of guesses. The word was " + secretWord +
               ".")
  
   # When you've completed your hangman function, uncomment these two lines
   # and run this file to test! (hint: you might want to pick your own
   # secretWord while you're testing)
  
   secretWord = chooseWord(wordlist).lower()
   hangman(secretWord)