Railroad Construction: Added initial boilerplate

Railroad-Construction/README.md

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+# Lab 12: Railroad Construction
+
+## Specification
+
+There are _n_ cities that want to create a shared train network so that each
+pair of cities is connected by rail to each of the other cities. The cost of
+laying track is directly proportional to the distance between two cities. The
+cost to lay one mile of railroad track is $1M. Your task is to determine the
+lowest cost possible for laying the track so that all the cities are connected.
+
+## Input
+
+A single line containing the number n of cities followed by n city coordinate
+lines. Each of the coordinate lines is a pair of floating point numbers x y
+giving the coordinates of the cities on a square grid (for this problem you may
+assume the earth is flat and that the units of the grid structure are given in
+miles).
+
+## Output
+
+The minimum amount of money (in millions) that must be spent to create the
+railroad network. You can round this to a single decimal place.
+
+<table>
+    <tr>
+        <td>Sample Input</td>
+        <td>Sample Output</td>
+    </tr>
+    <tr>
+        <td><pre>
+3
+0 1.5
+1 0
+0 0</pre></td>
+        <td><pre>$2.5M</pre></td>
+    </tr>
+    <tr>
+        <td><pre>
+8
+0 0
+1 1
+0 1
+3 3
+4 5
+2 2
+1 0
+3 2</pre></td>
+        <td><pre>$8.7M</pre></td>
+    </tr>
+</table>
+
+## Hints
+
+1. You may use our [connected_components.py](./connected_components.py) Download
+   connected_components.py in your code if you want., which will produce labels
+   for each of the vertices that correspond to their component. You will need to
+   use the adjacency list structure as suggested below if you wish to use this
+   code in its unmodified state.
+2. You may have already envisioned a way to represent this problem as a graph.
+   Draw the graph in the small example above on paper. How many edges does it
+   have? If you are unsure of this, check with me before you start coding the
+   solution.
+
+## Adjacency List
+
+Augment your dictionary/set based adjacency structure to use a dictionary for
+the edges (instead of a set as before). This will allow you to store the edge
+weights as the values of this second dictionary.
+
+## Method/Programming requirement
+
+Your program must implement either Borůvka's algorithm (I suggest you use
+Borůvka's) or Prims (not Kruskal). You must specify which algorithm you are
+implementing in the comments. Any other method to compute the answer will result
+in zero credit.
+
+## Submission
+
+Submit the code in a file named [cs412_railroad_a.py](./cs412_railroad_a.py) to
+Gradescope. If you use the supplied copy of
+[connected_components.py](./connected_components.py), you only need to import it
+into your code (it will be available on Gradescope, so, no need to submit). If
+you change connected_components.py, then please rename it and submit it as part
+of your code (or you can copy/paste the code into your lab and just submit a
+single file, it is up to you). You can import the code using the following
+python:
+
+```
+from connected_components import count_and_label
+```