- When you need to compare strings where the order isn't important (like anagram), you may consider using a hash map as a counter. If your language has a built-in `Counter` class like Python, ask to use that instead.
- If you need to keep a counter of characters, a common mistake to make is to say that the space complexity required for the counter is O(n). The space required for a counter is O(1) not O(n), because the upper bound is the range of characters which is usually a fixed constant of 26 when the input set is just lower case Latin characters.
- Common data structures for looking up strings efficiently:
- Find if a given string matches any path in a labeled graph. A path may contain cycles.
- Given a bipartite graph, separate the vertices into two sets.
- You are a thief trying to sneak across a rectangular field. There are alarms placed on the fields and they each have a circular sensing radius which will trigger if anyone steps into it. Each alarm may not have the same radius. Determine if you can get from one end of the field to the other end.
- You are a thief trying to sneak across a rectangular 100 x 100m field. There are alarms placed on the fields and they each have a circular sensing radius which will trigger if anyone steps into it. Each alarm has its own radius. Determine if you can get from one end of the field to the other end.
- Given a graph and two nodes, determine if there exists a path between them.
- [Building the DOM faster: speculative parsing, async, defer and preload](https://hacks.mozilla.org/2017/09/building-the-dom-faster-speculative-parsing-async-defer-and-preload/)
Yangshun Tay
7 years ago
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GitHub