Merge pull request #47 from nbro/iss20

Iss20 should be solved

ands/ds/BST.py

@@ -2,13 +2,18 @@
 # -*- coding: utf-8 -*-
 
 """
+# Meta info
+
 Author: Nelson Brochado
 
-Creation: July, 2015
+Created: 01/07/2015
+
+Updated: 28/08/2016
+
+# Description
 
-Last update: 28/08/2016
+### Coding Conventions
 
-## Names' Conventions
 In general, if a variable name has more than one word,
 those words are separated by _ (underscores).
 Functions' names should roughly describe what the function does.
@@ -17,11 +22,13 @@
 comments are usually provide on the first occurrence of the name,
 in order to explain the purpose of such a variable.
 
-### Functions
+#### Functions
+
 - Methods that start with _ should not be called,
 because they might either be "helper" or private functions.
 
-### Parameters
+#### Parameters
+
 - `u`, `v`, `z` and `w` are used to indicate that a general `BSTNode` object is expected.
 
 - `s` is used to indicate that a source node is expected.
@@ -31,12 +38,14 @@
 
 - `ls` is usually used to indicate that a list or a tuple is expected.
 
-### Local Variables
+#### Local Variables
+
 - `c` usually indicates some "current" changing variable.
 
 - `p` is usually `c`'s parent.
 
-### Docstrings
+#### Docstrings
+
 Under methods' signatures, h in O(h) is the height of the tree.
 Note that the height of a BST varies depending on how elements
 are inserted and removed.
@@ -46,25 +55,22 @@
 Other names are self-descriptive.
 For example, "key" and "value" are self-descriptive.
 
-## Resources
-
-- [https://en.wikipedia.org/wiki/Binary_search_tree](https://en.wikipedia.org/wiki/Binary_search_tree)
-
-- [Introduction to Algorithms (3rd edition)](https://mitpress.mit.edu/books/introduction-algorithms) by CLRS, chapter 12
+# TODO
 
-- [http://algs4.cs.princeton.edu/32bst/](http://algs4.cs.princeton.edu/32bst/)
-
-- [http://www.cs.princeton.edu/courses/archive/spr04/cos226/lectures/bst.4up.pdf](http://www.cs.princeton.edu/courses/archive/spr04/cos226/lectures/bst.4up.pdf
-)
-
-- [http://algs4.cs.princeton.edu/32bst/BST.java.html](http://algs4.cs.princeton.edu/32bst/BST.java.html)
-
-## TODO
 - Improve the "randomness" of insertion into the BSTImproved class.
 - Add functions "intersection" and "union".
 - Implement a recursive version of insert (OPTIONAL).
 - implement "is balanced" function (http://codereview.stackexchange.com/questions/108459/binary-tree-data-structure)
 - Maybe the methods of the BSTNode need an improvement in terms of implementation...
+
+# Resources
+
+- [https://en.wikipedia.org/wiki/Binary_search_tree](https://en.wikipedia.org/wiki/Binary_search_tree)
+- [Introduction to Algorithms (3rd edition)](https://mitpress.mit.edu/books/introduction-algorithms) by CLRS, chapter 12
+- [http://algs4.cs.princeton.edu/32bst/](http://algs4.cs.princeton.edu/32bst/)
+- [http://www.cs.princeton.edu/courses/archive/spr04/cos226/lectures/bst.4up.pdf](http://www.cs.princeton.edu/courses/archive/spr04/cos226/lectures/bst.4up.pdf)
+- [http://algs4.cs.princeton.edu/32bst/BST.java.html](http://algs4.cs.princeton.edu/32bst/BST.java.html)
+
 """
 
 from random import randint

ands/ds/DSForests.py

@@ -2,15 +2,15 @@
 # -*- coding: utf-8 -*-
 
 """
-## Meta info
+# Meta info
 
 Author: Nelson Brochado
 
-Creation: 21/02/16
+Created: 21/02/2016
 
-Last update: 03/01/16
+Updated: 03/01/2016
 
-## Description
+# Description
 
 A disjoint-set (forests) or union-find data structure is a data structure which keeps track of a set of elements
 partitioned into disjoint (non-overlapping, i.e. their intersection is the empty set) sets.
@@ -31,34 +31,26 @@
 
 These two techniques complement each other: applied together, the amortized time per operation is only O( α (n)).
 
-## References
+# TODO
 
-- Introduction to algorithms, 3rd, by C.L.R.S., chapter 21.3
+- Deletion operation (OPTIONAL, since it's usually not part of the interface of a disjoint-set data structure)
+- Pretty-print(x), for some element x in the disjoint-set data structure.
+- Implement the version explained [here](http://algs4.cs.princeton.edu/15uf/)
 
-- [https://en.wikipedia.org/wiki/Disjoint-set_data_structure](https://en.wikipedia.org/wiki/Disjoint-set_data_structure)
+# References
 
+- Introduction to algorithms, 3rd, by C.L.R.S., chapter 21.3
+- [https://en.wikipedia.org/wiki/Disjoint-set_data_structure](https://en.wikipedia.org/wiki/Disjoint-set_data_structure)
 - [http://orionsword.no-ip.org/blog/wordpress/?p=246](http://orionsword.no-ip.org/blog/wordpress/?p=246)
-
 - [http://stackoverflow.com/a/22945492/3924118](http://stackoverflow.com/a/22945492/3924118)
-
 - [http://stackoverflow.com/q/23055236/3924118](http://stackoverflow.com/q/23055236/3924118)
-
 - [https://www.cs.usfca.edu/~galles/JavascriptVisual/DisjointSets.html](https://www.cs.usfca.edu/~galles/JavascriptVisual/DisjointSets.html)
 to visualize how disjoint-sets work.
 
-## TODO
-
-- Deletion operation (OPTIONAL, since it's usually not part of the interface of a disjoint-set data structure)
-
-- Pretty-print(x), for some element x in the disjoint-set data structure.
-
-- Implement the version explained [here](http://algs4.cs.princeton.edu/15uf/)
-
 """
 
 
 class DSNode:
-
     def __init__(self, x, rank=0):
         # This attribute can contain any hashable value.
         self.value = x
@@ -97,7 +89,6 @@ def __repr__(self):
 
 
 class DSForests:
-
     def __init__(self):
         # keeps tracks of the DSNodes in this disjoint-set forests.
         self.sets = {}

ands/ds/HashTable.py

@@ -2,11 +2,15 @@
 # -*- coding: utf-8 -*-
 
 """
+# Meta info
+
 Author: Nelson Brochado
 
-Creation: June, 2015
+Created: 01/06/2015
+
+Updated: 21/02/2016
 
-Last update: 21/02/16
+# Description
 
 Hash table that re-sizes if no more slot is available.
 The process of re-sizing doubles the current capacity of the hash table each time (for now).
@@ -19,10 +23,11 @@
     h[12] = 3
     print(h[12])
 
-## References
-- [http://interactivepython.org/runestone/static/pythonds/SortSearch/Hashing.html](http://interactivepython.org/runestone/static/pythonds/SortSearch/Hashing.html)
+# References
 
+- [http://interactivepython.org/runestone/static/pythonds/SortSearch/Hashing.html](http://interactivepython.org/runestone/static/pythonds/SortSearch/Hashing.html)
 - [http://stackoverflow.com/questions/279539/best-way-to-remove-an-entry-from-a-hash-table](http://stackoverflow.com/questions/279539/best-way-to-remove-an-entry-from-a-hash-table)
+
 """
 
 from tabulate import tabulate