Data structure and algorithm. https://algs4.cs.princeton.edu/home/ (This website to learn Data Structure And Algorithm) https://www.youtube.com/watch?v=1QZDe28peZk&list=PLRdD1c6QbAqJn0606RlOR6T3yUqFWKwmX&index=1 (This is the youtube video lectures) Algorithm: Method for solving a problem. Data structure: Method to store information. data type-> stack, queue, bag, union find , priority queue sorting-> quicksort, mergesort, heapsort, radix sorts searching-> BST, red-black BST, hash table graphs-> BFS, DFS, Prim, Kruskal , Dijkstra string-> KMP, regular expressions, TST, Huffman, LZW advanced-> B-tree, suffix array, maxflow