add readme with links

README.md

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+# Grokking Algorithms 2E v4
+
+### Binary Search
+
+[chapter1][binary]
+
+### Selection Sort
+
+[chapter2][selection_sort]
+
+### Recursion
+
+[chapter3][recursion]
+
+### Quicksort
+
+[chapter4][quick_sort]
+
+### Breadth-First Search
+
+[chapter6][quick_sort]
+
+### Trees
+
+[chapter7][trees]
+
+### Dijkstra
+
+[chapter9][dijkstra]
+
+### Greedy
+
+[chapter10][greedy]
+
+### Dynamic Programming
+
+[chapter11][dynamic]
+
+### K-Nearest Neighbours
+
+[chapter12][knn]
+
+[binary]: ./chapter1/
+[selection_sort]: ./chapter2/
+[recursion]: ./chapter3/
+[quick_sort]: ./chapter4/
+[bfs]: ./chapter6/
+[trees]: ./chapter7/
+[dijkstra]: ./chapter9/
+[greedy]: ./chapter10/
+[dynamic]: ./chapter11/
+[knn]: ./chapter12/