contents(sorting): add video resources to sorting and searching (#567)

apps/website/contents/algorithms/sorting-searching.md

@@ -44,6 +44,13 @@ While you're unlikely to be asked to implement a sorting algorithm from scratch
   - [Pivoting To Understand Quicksort (Part 2)](https://medium.com/basecs/pivoting-to-understand-quicksort-part-2-30161aefe1d3), basecs
   - [Counting Linearly With Counting Sort](https://medium.com/basecs/counting-linearly-with-counting-sort-cd8516ae09b3), basecs
   - [Getting To The Root Of Sorting With Radix Sort](https://medium.com/basecs/getting-to-the-root-of-sorting-with-radix-sort-f8e9240d4224), basecs
+- Videos
+  - [Heapsort](https://youtu.be/ryRfapIQHW0) ([slides](https://samuelalbanie.com/files/digest-slides/2022-12-brief-guide-to-heapsort-and-binary-heaps.pdf)), Samuel Albanie, University of Cambridge
+  - [Quicksort](https://youtu.be/kbiKn1K08RM) ([slides](https://samuelalbanie.com/files/digest-slides/2023-01-brief-guide-to-quicksort.pdf)), Samuel Albanie, University of Cambridge
+  - [Lower bounds for comparison sorts](https://www.youtube.com/watch?v=JWSiXs9aB5U) ([slides](https://samuelalbanie.com/files/digest-slides/2023-01-2023-01-brief-guide-to-comparison-sorting-lower-bounds.pdf)), Samuel Albanie, University of Cambridge
+  - [Counting sort](https://www.youtube.com/watch?v=0aMcZpAySjw) ([slides](https://samuelalbanie.com/files/digest-slides/2023-01-brief-guide-to-counting-sort.pdf)), Samuel Albanie, University of Cambridge
+  - [Radix sort](https://www.youtube.com/watch?v=HzPbzQi9404) ([slides](https://samuelalbanie.com/files/digest-slides/2023-01-brief-guide-to-radix-sort.pdf)), Samuel Albanie, University of Cambridge
+  - [Bucket sort](https://www.youtube.com/watch?v=mz2fBJyoEVc) ([slides](https://samuelalbanie.com/files/digest-slides/2023-01-brief-guide-to-bucket-sort.pdf)), Samuel Albanie, University of Cambridge 
 
 ## Time complexity