Add README and LICENCE

LICENCE

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+MIT License
+
+Copyright (c) [2022] [Stefanos Iosifidis]
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+
+# R-Tree
+This project demonstrates the construction of an R-Tree using the Morton
+space filling curve. 
+
+## Bulk-loading
+For every object of the collection, we calculate the z-order value of its center and sort
+the collection based on it. Using this technique we want nodes created in the upper levels
+to contain objects that are as close to each other as possible. We set the maximum capacity
+of a node to 20. To utilize disk space properly at least 40% of each node should be full.
+With that in mind, every node except the root should have at least 8 nodes.
+
+## Range query
+Given a window size, recursively search the tree from top to bottom for the nodes that
+intersect the window. When reaching the leaf nodes stop. Every object from the leaf nodes
+that still intersects the window is a hit.
+
+## Nearest Neighbor Query
+A heap queue stores the child nodes of the root node, based on the distance from the
+point query. Iteratively pop a node from the heap queue and then push its child nodes in it.
+When reaching a leaf node, put the objects into the heap queue. Finally, if the heap queue
+is about to pop an object, this is the first neighbor hit. Continue until reaching the number
+of neighbors requested.
+
+## Run Locally
+
+Clone the project
+```bash
+  git clone --recursive https://github.com/stefiosif/rtree
+```
+
+Construct the R-Tree
+```bash
+  make build
+```
+
+Run all range queries given on `data/ranges.txt`
+```bash
+  make range
+```
+
+Run all knn queries given on `data/knn.txt` where k is specified (e.g. k=10)
+```bash
+  make knn k=10
+```
+