deque | 易学教程

Deque vs Queue Speed

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问题 I was working on a problem on LeetCode (Here). When I finished the problem, I came up with: class MovingAverage { std::deque<int> numsToAverage; int maxSize; int currentTotal; public: /** Initialize your data structure here. */ MovingAverage(int size) { maxSize = size; currentTotal = 0; } double next(int val) { currentTotal += val; numsToAverage.push_back(val); if (numsToAverage.size() > maxSize) { currentTotal -= numsToAverage[0]; numsToAverage.pop_front(); } return (double)currentTotal /

Vector and deque initialization or push_back causes SIGABRT error

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问题 I'm getting a weird error, when initializing my deque or vector. I'm using QtCreator and a CMake-Project. If I use a deque, it aborts on initialization: std::deque<int> myValues; // <-- abort here for (int i=0;i<10;++i) { myValues.push_back(i); } when I use deque, it aborts on push_back: std::vector<int> myValues; for (int i=0;i<10;++i) { myValues.push_back(i); // <-- abort here } I can't find out why this is happening now (it worked that way all the time). Both aborts happen inside _gnu_cxx:

Building a multithreaded work-queue (consumer/producer) in C++

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问题 I have the following scenario: I have a single thread that is supposed to fill a container with pairs of integers (in essence, task descriptions), and I have a large number of worker threads (8-16) that should take elements from this container and perform some work. I thought the problem could be easily solved by a blocking queue -- e.g. on item-removal, threads synchronize access to the queue, and sleep if there is no data available. I (perhaps wrongly) assumed that something like this

Building a multithreaded work-queue (consumer/producer) in C++

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C++ deque: when iterators are invalidated

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问题 Please correct me if I am wrong. Thank you! insert and erase will relocate elements, but elements before the position where insertion/erasure takes place don't relocate and hence their iterators remain valid. push_back and pop_back don't invalidate any iterators. push_front and pop_front invalidate all iterators. swap won't relocate elements, but somehow I think it should invalidate iterators. 回答1: push_back() and push_front() are defined in terms of insert() . Similarly, pop_back() and pop

Queue performance wise which is better implementation - Array or Linked list

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问题 Which way gives the faster enqueueing and dequeuing when I have to insert very few elements, Is array better than a linked list? I need to insert few element and I have to remove and read that removed element from queue. If it is array I may have to modify the indexes every time I remove an element. Inserting and deleting may happen simultaneously also. Which one is better from below case? typedef struct{ mylist list; struct mylistQ *next; }mylistQ; Array Code static mylist myListQ[QUEUESIZE

python: deque vs list performance comparison

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问题 In python docs I can see that deque is a special collection highly optimized for poping/adding items from left or right sides. E.g. documentation says: Deques are a generalization of stacks and queues (the name is pronounced “deck” and is short for “double-ended queue”). Deques support thread-safe, memory efficient appends and pops from either side of the deque with approximately the same O(1) performance in either direction. Though list objects support similar operations, they are optimized

【STL记录】Containers--Deques

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> Deque和vector很像，区别是deque可以在两头插入和删除。要使用deque，需加上头文件： #include <deque> 一、Abilities of Deque 1.deque与vector的不同之处在头尾插入和移除元素都很快访问元素的内部结构更加间接，因此访问和移动稍慢 Iterator必需是smart pointer而不是ordinary pointer，因为要在不同blocks之间跳 deque能包含更多的元素，所以max_size()更大一些 Deques不提供控制capacity和再分配的支持当不在使用时，内存空间将释放所以，当满足一下条件时，使用deque：在两端插入和移除元素不指向Container的元素重要的一点是当不再使用时container会释放内存（并不能保证一定会发生） 2.Constructors and Destructor Operation Effect deque<Elem> c Default constructor：创建一个空的deque deque<Elem> c(c2) Copy constructor：通过复制c2创建c deque<Elem> c = c2 Copy constructor：通过复制c2创建c deque<Elem>

Double-sided queue problem

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问题 I am trying to run this method to insert a generic value (EltType) into an double sided queue(deque), but I keep getting an outOfBoundsException that I just can't figure out. Would anyone please be able to help me with this ? This is just an extract from the code, but I think it can be pieced together from this! private final int CAPACITY = 10; private int capacity; private int end; private EltType deque[]; public ArrayBasedDeque() { this.capacity = CAPACITY; deque = (EltType[]) (new Object

Does binary search have logarithmic performance of deque C++ data structure?

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问题 The standard says that std::binary_search(...) and the two related functions std::lower_bound(...) and std::upper_bound(...) are O(log n) if the data structure has random access. So, given that, I presume that these algorithms have O(log n) performance on std::deque (assuming its contents are kept sorted by the user). However, it seems that the internal representation of std::deque is tricky (it's broken into chunks), so I was wondering: does the requirement of O(log n) search hold for std: