From 438a9eeb430addd2e7dd69e2d175daacdc82489e Mon Sep 17 00:00:00 2001
From: SCAUFINN <finnpolar@163.com>
Date: Fri, 28 Jun 2019 11:50:44 +0800
Subject: [PATCH 1/3] Update invert_dict.py

---
 code/invert_dict.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/code/invert_dict.py b/code/invert_dict.py
index 01588e3..8a569f9 100644
--- a/code/invert_dict.py
+++ b/code/invert_dict.py
@@ -17,9 +17,9 @@ def invert_dict(d):
 
     Returns: dict
     """
-    inverse = {}
-    for key, val in d.iteritems():
-        inverse.setdefault(val, []).append(key)
+    inverse = {}  # create an empty dictionary
+    for key, val in d.iteritems(): # loop the dictionary
+        inverse.setdefault(val, []).append(key) # if not exist, create a new list
     return inverse
 
 

From 3cc3f50ec3bf808bfd619dba6974920901fec8e0 Mon Sep 17 00:00:00 2001
From: SCAUFINN <finnpolar@gmail.com>
Date: Fri, 28 Jun 2019 15:00:11 +0800
Subject: [PATCH 2/3] Update rotate_pairs.py

---
 code/rotate_pairs.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/code/rotate_pairs.py b/code/rotate_pairs.py
index 0a98464..694494e 100644
--- a/code/rotate_pairs.py
+++ b/code/rotate_pairs.py
@@ -15,9 +15,9 @@ def make_word_dict():
     that contains the words as keys"""
     d = dict()
     fin = open('words.txt')
-    for line in fin:
+    for line in fin: 
         word = line.strip().lower()
-        d[word] = word
+        d[word] = word # create a list[] dict d
 
     return d
 

From 1c450b84d9fda5c14f07461915fec01fefceffcf Mon Sep 17 00:00:00 2001
From: SCAUFINN <finnpolar@163.com>
Date: Fri, 28 Jun 2019 16:29:55 +0800
Subject: [PATCH 3/3] Update rotate_pairs.py

---
 code/rotate_pairs.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/code/rotate_pairs.py b/code/rotate_pairs.py
index 694494e..fa170e6 100644
--- a/code/rotate_pairs.py
+++ b/code/rotate_pairs.py
@@ -9,6 +9,32 @@
 
 from rotate import rotate_word
 
+'''
+def rotate_letter(letter, n):
+    """Rotates a letter by n places.  Does not change other chars.
+    letter: single-letter string
+    n: int
+    Returns: single-letter string
+    """
+    
+    start = ord('a')
+
+    c = ord(letter) - start
+    i = (c + n) % 26 + start
+    return chr(i)
+
+def rotate_word(word, n):
+    """Rotates a word by n places.
+    word: string
+    n: integer
+    Returns: string
+    """
+    
+    res = ''
+    for letter in word:
+        res += rotate_letter(letter, n)
+    return res
+'''
 
 def make_word_dict():
     """Read the words in words.txt and return a dictionary