Added k-D trees, suffix arrays.

README.md

@@ -100,6 +100,7 @@ sometimes word-for-word in Google's coaching notes.
     - [Locality-Sensitive Hashing](#locality-sensitive-hashing)
     - [van Emde Boas Trees](#van-emde-boas-trees)
     - [Augmented Data Structures](#augmented-data-structures)
+    - [k-D Trees](#k-d-trees)
     - [Skip lists](#skip-lists)
     - [Network Flows](#network-flows)
     - [Disjoint Sets & Union Find](#disjoint-sets--union-find)
@@ -1196,6 +1197,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
         - [Boyer-Moore String Search Algorithm](https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_string_search_algorithm)
         - [Advanced String Searching Boyer-Moore-Horspool Algorithms (video)](https://www.youtube.com/watch?v=QDZpzctPf10)
     - [ ] [Coursera: Algorithms on Strings](https://www.coursera.org/learn/algorithms-on-strings/home/week/1)
+    - [ ] [Suffix Arrays (video)](https://www.youtube.com/watch?v=HKPrVm5FWvg)
 
 ---
 
@@ -1610,6 +1612,12 @@ You're never really done.
 - ### Augmented Data Structures
     - [ ] [CS 61B Lecture 39: Augmenting Data Structures](https://youtu.be/zksIj9O8_jc?list=PL4BBB74C7D2A1049C&t=950)
 
+- ### k-D Trees
+    - great for finding number of points in a rectangle or higher dimension object
+    - a good fit for k-nearest neighbors
+    - [ ] [Kd Trees (video)](https://www.youtube.com/watch?v=W94M9D_yXKk)
+    - [ ] [kNN K-d tree algorithm (video)](https://www.youtube.com/watch?v=Y4ZgLlDfKDg)
+
 - ### Skip lists
     - "These are somewhat of a cult data structure" - Skiena
     - [ ] [Randomization: Skip Lists (video)](https://www.youtube.com/watch?v=2g9OSRKJuzM&index=10&list=PLUl4u3cNGP6317WaSNfmCvGym2ucw3oGp)