added the problems for the rest of the book

ch11/11.01.py

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+# Write a function that reads the words in words.txt and stores them as keys
+# in a dictionary. It doesn't matter what the values are. Then you can use
+# the in operator as a fast way to check whether a string is in the 
+# dictionary. If you did Exercise 10.8, you can compare the speed of this
+# implementation with the list in operator and the bisection search.
+

ch11/11.02.py

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+# Dictionaries have a method called get that takes a key and a default
+# value. If the key appears in the dictionary, get returns the 
+# corresponding value; otherwise it returns the default value.
+# For example:
+# >>> h = histogram('a')
+# >>> print h
+# {'a': 1}
+# >>> h.get('a', 0)
+# 1
+# >>> h.get('b', 0)
+# 0
+# Use get to write histogram more concisely. You should be able to 
+# eliminate the if statement

ch11/11.03.py

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+# Dictionaries have a method called keys that returns the keys of the 
+# dictionary, in no particular order, as a list.
+# Modify print_hist to print the keys and their values in alphabetical order.
+
+

ch11/11.04.py

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+# Modify reverse_lookup so that it builds and returns a list of all keys
+# that map to v, or an empty list if there are none.
+

ch11/11.05.py

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+# Read the documentation of the dictionary method setdefault and use it 
+# to write a more concise version of invert_dict.
+

ch11/11.06.py

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+# Run this version of fibonacci and the original with a range of parameters
+# and compare their run times.
+
+

ch11/11.07.py

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+# Exponentiation of large integers is the basis of common algorithms for
+# public-key encryption. Read the Wikipedia page on the RSA algorithm and
+# write functions to encode and decode messages.
+
+

ch11/11.08.py

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+# If you did Exercise 10.5, you already have a function named 
+# has_duplicates that takes a list as a parameter and returns True if 
+# there is any object that appears more than once in the list.
+# Use a dictionary to write a faster, simpler version of has_duplicates.
+

ch11/11.09.py

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+# Two words are "rotate pairs" if you can rotate one of them and get the 
+# other (see rotate_word in Exercise 8.12).
+# Write a program that reads a wordlist and finds all the rotate pairs.
+

ch11/11.10.py

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+# Here's another Puzzler from Car Talk :
+# This was sent in by a fellow named Dan O'Leary. He came upon a common one-
+# syllable, five-letter word recently that has the following unique property.
+# When you remove the first letter, the remaining letters form a homophone of
+# the original word, that is a word that sounds exactly the same. Replace the
+# first letter, that is, put it back and remove the second letter and the 
+# result is yet another homophone of the original word. And the question is, 
+# what's the word?
+# Now I'm going to give you an example that doesn't work. Let's look at the 
+# five-letter word, 'wrack.' W-R-A-C-K, you know like to 'wrack with pain.' If
+# I remove the first letter, I am left with a four-letter word, 'R-A-C-K.' As 
+# in, 'Holy cow, did you see the rack on that buck! It must have been a
+# nine-pointer!' It's a perfect homophone. If you put the 'w' back, and remove
+# the 'r,' instead, you're left with the word, 'wack,' which is a real word, 
+# it's just not a homophone of the other two words. But there is, however, at 
+# least one word that Dan and we know of, which will yield two homophones if 
+# you remove either of the first two letters to make two, new four-letter words. # The question is, what's the word?
+# You can use the dictionary from Exercise 11.1 to check whether a string is in
+# the word list.
+# To check whether two words are homophones, you can use the CMU Pronouncing 
+# Dictionary. You can download it from 
+# www.speech.cs.cmu.edu/cgi-bin/cmudict or from thinkpython.com/code/c06d 
+# and you can also download thinkpython.com/code/pronounce.py, which provides
+# a function named read_dictionary that reads the pronouncing dictionary and 
+# returns a Python dictionary that maps from each word to a string that 
+# describes its primary pronunciation.
+# Write a program that lists all the words that solve the Puzzler. You can see
+# my solution at thinkpython.com/code/homophone.py.
+
+
+