![]() ![]() These are the leading keys, getting the value associated with a key, checking if a key exists in the priority queue, getting the key index with the smallest value, getting smallest value in the index Burcu being able to insert and update key value pairs. We can think of an index party queue as an abstract data type with certain operations we want it to support here are about a dozen or so operations, we want our index particular support. It's already there implicitly, however, it is handy to be able to support any type of key such as names, or general objects. So there's no need to actually construct this bi directional mapping. I will say though, that often and I mean, very often, the keys themselves are already integers in the range zero to n. So we want to facilitate being able to index into those arrays. The reason for this is that typically part of queues are implemented as heaps, which under the hood are actually arrays. So you're probably wondering why I'm saying that we need to map keys to indices in the domain zero to n non inclusive. ![]() Basically, any operation on the index party q will require the associated key index of a particular key. So I would advise using a bi directional hash table to be able to flip back and forth between the key and its key index. Note that this mapping is intended to be bi directional. We use an index persecutor to track who should get served next in our hospital, we need to assign each person a unique key index value between zero and n non inclusive. The first step to using an index party queue is to assign index values to all the keys, thus forming a bi directional mapping. ![]() The index party queue is a data structure which lets us do this efficiently. As we saw in the hospital example, it is very important to be able to dynamically update the priority of certain people. Once now he does that with a car wash should be next. During this time, Richard gets impatient and leaves, he goes to another clinic down the street, so he no longer needs to be accounted for.įurther suppose that a car wash goes to take a drink of water slips on the floor, and as a result cracks his head and needs immediate attention. Because of this Nadir gets served next, once they're finished with James. However, then something happens suppose Nader's stomach condition worsens, and she started vomiting, her priority needs to get a bit to six. This means the hospital would serve Mary first Followed by James. We want to process these patients by highest priority first. Richard has a fractured wrist so his priority is five.Īnd lastly, Leah also has a stomach that hurts. Now you just stomach hurts, she gets priority of three. James has an arrow in his leg, he has a priority of seven. A car she has a paper cut, he has a priority of one. Each person in the waiting room has a certain condition that needs to be dealt with.įor instance, Mary is in labor. Suppose a hospital has a waiting room with n people, which need different levels of attention. One of the big problems that the index party queue solves is being able to quickly look up and dynamically change the values in your priority queue on the fly, which is often very useful. So what exactly is an indexed party queue? Well, it's a traditional priority queue variant which on top of having all the regular priority queue operations, also supports quick updates and deletes of key value pairs. But for those of you who want to know, priority queues and full detail, please check out the description for links to those. Strictly speaking, you can probably get by without watching all those videos as I will be doing a quick recap. ![]() So just before we get started, this video builds off concepts from the previous parody videos, which simply go over the basics. This is going to prove to be a very useful data structure that you wish you would have known a long time ago. My name is William and today's data structure is the indexed priority queue. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |