deque accessibility

C + + in the STL is still more useful, especially in the implementation of scientific research algorithms, but also useful, but not how the system has been studied, so recently looked for a book, Ye Zhijun the "C + + STL development Technology Guidance", science, the nature of a book, written relatively shallow [hehe, do not spray ]。 Most of the content below is excerpted from the book.Deque double-ended queue container (double-ended queue), can be inserted in the tail, head, delete elements, th

operations at both ends: push_back, push_front, pop_back, pop_front, etc, in addition, the operation efficiency on both ends is similar to that on list.Therefore, in actual use, how to select one of the three containers should be determined according to your needs. Generally, the following principles should be followed:1. If you need efficient instant access without worrying about the efficiency of insertion and deletion, use the Vector2. If you need to insert and delete a large number of objec

Create a two-way queueImport COLLECTIONSD = Collections.deque ()Append (add an element to the right)Import COLLECTIONSD = Collections.deque () d.append (1) d.append (2) print (d) #输出: Deque ([1, 2])Appendleft (add an element to the left)Import COLLECTIONSD = Collections.deque () d.append (1) d.appendleft (2) print (d) #输出: Deque ([2, 1])Clear (Empty queue)Import COLLECTIONSD = Collections.deque () d.append

Create a two-way queueImport COLLECTIONSD = Collections.deque ()Append (add an element to the right)Import COLLECTIONSD = Collections.deque () d.append (1) d.append (2) print (d) #输出: Deque ([1, 2])Appendleft (add an element to the left)Import COLLECTIONSD = Collections.deque () d.append (1) d.appendleft (2) print (d) #输出: Deque ([2, 1])Clear (Empty queue)Import COLLECTIONSD = Collections.deque () d.append

#2: Deque also provides append and Pop methods that can be executed at the same speed at both ends of the sequence#例子2: Implement FIFO using Deque, as follows:From collections Import DequeImport Profile,statImport SysQeque=deque ()def add1 (data):Qeque.append (data)Def add2 ():Qeque.pop ()big_n=100000@profile (' deque

To create a deque sequence: From collections import deque d = deque () Deque provides a list-like approach to operations: D = deque () d.append (' 1 ') d.append (' 2 ') d.append (' 3 ') len (d) d[0] d[-1] Output results: 3

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Deque is an abbreviation for double-ended queue, similar to list, but provides an action to insert and delete at both ends. Appendleft inserts to the left of the list Popleft the value on the left side of the pop-up list Extendleft extension on the left For example: Queue = Deque () # append values to wait for processing queue.appendleft ("a") Queue.appendleft ("second" Queue.appen

Create a Deque sequence: From collections import dequed = deque () Deque provides a list-like operation method: D = deque () d. append ('1') d. append ('2') d. append ('3') len (d) d [0] d [-1] Output result: 3 '1' 3' Both ENDS Use pop: D = deque ('000000') len (d) d.

Back to General bookIn the original section: http://www.cplusplus.com/reference/deque/deque/1. std::d equeTemplate Dual-ended queuesDeque (pronounced like "deck") is a special abbreviation for Double-ended-queUE. Deque is a dynamic-length sequence container that can be extended to either end or shortened from either end.Different libraries have different implemen

Snow", 18, 175]) # Access Print ( Info._asdict ())　　　　Defaultdictis a dict extension class that accesses the dictionary key if it is not, automatically sets the default value and adds the dictionaryinfo = dict () name = Info.setdefault (' name ', "North Gate Blown Snow") print (name, info) from collections import defaultdict# default value must be an iterative object info = Defaultdict (lambda: "North gate blowing Snow") name = info[' name ']print (name, info)　　

Deque is an abbreviation for the double-ended queue, similar to list, but provides an operation to insert and delete at both ends. Appendleft inserts to the left of the list Popleft the value to the left of the popup list Extendleft extension on the left For example: Queue = Deque () # Append values to wait for Processingqueue.appendleft ("first") Queue.appendleft ("second") Queue.appendlef

#include The deque bidirectional queue is a continuous linear space with two-way openings that efficiently insert and delete elements at both ends of the deque and are very similar to vectors on the interface Function Describe C.assign (Beg,end)C.assign (N,elem) Assigns the data in the [beg; end] Interval to C.Assigns a copy of n elem to C. c.at (IDX) Return

Create a two-way queueImport= Collections.deque ()Append (add an element to the right)Import= collections.deque () d.append (1) d.append (2)print(d) # output: deque ([1, 2])Appendleft (add an element to the left)Import= collections.deque () d.append (1) d.appendleft (2)print (d) # output: Deque ([2, 1])Clear (Empty queue)Import= collections.deque () d.append (1) d.clear ()print(d) # output:

First, when considering the memory allocation and execution performance, it is better to use std: deque than std: vector. Deque Overview Deque and vector are both in the standard template library. deque is a dual-end queue, which is very similar to vector in the interface and can be directly replaced in many operations

/****************************************** ***** Deque:**************************************** ******* Random access is allowed. elements are inserted and deleted in the ** header and tail **. the time complexity is O (1)* Random Access container back insertion sequence front Insertion Sequence***************************************** **************************************** ***** Deque is more advantageo

Create a two-way queue Import COLLECTIONSD = Collections.deque () Append (add an element to the right) Import COLLECTIONSD = Collections.deque () d.append (1) d.append (2) print (d) #输出: Deque ([1, 2]) Appendleft (add an element to the left) Import COLLECTIONSD = Collections.deque () d.append (1) d.appendleft (2) print (d) #输出: Deque ([2, 1]) Clear (Empty queue) Import COLLECTIONSD = Collections.deque () d

In STL, the basic containers include string, vector, list, deque, set, and map. Set and map are unordered storage elements. They can only be accessed through the interfaces provided by it; Set: set, which is used to determine whether an element is in a group and is rarely used;Map: ing, which is equivalent to a dictionary. It maps a value to another value. If you want to create a dictionary, use it;The underlying layer uses a tree structure, most of w

); // delete all elements whose values are 11 in the linked list. 5. Reverse linked list Lt. Reverse (); // reverse the order of elements in the linked list 6. Order (Ascending by default) Lt. Sort (); 7. Delete adjacent duplicate elements Lt. Unique (); // you must first sort it by Lt. Sort (). After sorting, the same element must be adjacent. Deque usage Deque also uses dynamic arrays, but the memory mana

Ordered container: vector, deque, list, vectordeque 1. Ordered containers: vector, deque, list Containers share public interfaces. You only need to learn one type and use another type. Each container provides a set of different time and functions. Generally, you do not need to modify the code, order change type declaration, and each container type replaces another container type, the program performance can