tl;dw: - Tree Traversal (recursive and iterative) - BFS - DFS - Binary Search (log time) - Data structures to represent a tree - Elegant recursion (with helper functions) - know the limits of recursion - know how to convert to an iterative algo - Fibonacci - Stack and Queues - Given a string of parens, check if they're valid (use stack) - Object oriented programming (bring it up whenever you can) - class, parameters, public variables - Grid (2D array or Grid class?) - Hash Maps - Time space analysis, hashing function, collisions - Big O theory - Have different programming languages at your disposal, don't stick with PHP if you're interviewing for Java. - Sorting (bubble sort, merge sort) - Work with strings (palindrome, anagram) - "Dynamic programming" - Memoization
https://reddit.com/r/programming/comments/962zvx/top_algorithms_for_the_coding_interview_for/e3xr2rc?context=3