udacity data structures and algorithms

1. Code implementationdefMerge_sort (alist):ifLen (alist) : returnalist#two-part decompositionnum = Len (alist)/2 Left=Merge_sort (Alist[:num]) right=Merge_sort (alist[num:])#Merging returnmerge (Left,right)defmerge (left, right):" "merge operation, combine two ordered arrays left[] and right[] into a large ordered array" " #The subscript pointer to left and rightL, R =0, 0 result= [] whileL andrLen (right):ifLEFT[L] Right[r]: Result.append (Left[l]) L+ = 1Else: Result.append (R

1. How to find two pointsFind the fastest speed for a sorted list2. Code implementation(1) Recursive implementationdefBinary_search (Alist, item):ifLen (alist) = =0:returnFalseElse: Midpoint= Len (alist)//2ifalist[midpoint]==Item:returnTrueElse: ifitemAlist[midpoint]:returnBinary_search (Alist[:midpoint],item)Else: returnBinary_search (alist[midpoint+1:],item) testlist= [0, 1, 2, 8, 13, 17, 19, 32, 42,]Print(Binary_search (Testlist, 3))Print(Binary_search (Testlist, 13))(2) N

1. Principle:2. Code implementationdefQuick_sort (alist, Start, end):"""Quick Sort""" #Recursive exit conditions ifStart >=End:return #sets the starting element as the datum element to find the positionMID =Alist[start]#Low is the left-to-right cursor for the left of the sequenceLow =Start#High is the right-to-left cursor to the right of the sequenceHigh =End whileLow High :#If low is not coincident with high, the element with high points is not smaller than the datum element, then high

1. Basic properties of stacks and queues Stack is advanced after out; (like a bullet clip, a last-shot first) Queues are FIFO; (like waiting in line to buy ice cream, in order to take turns) Stack and queue in the implementation of the structure can have an array and a list of two forms; (1) The array structure is easy to implement;(2) The structure of the linked list is more complicated, because it involves a lot of pointer operation;1.1 Basic operation of stack structure(1) Pop op

()) { CharCH =Thestack.pop (); Output= output +ch; } returnoutput; } } classReverseapp { Public Static voidMain (string[] args)throwsIOException {String input, output; while(true) {System.out.print ("Enter A string:"); System.out.flush (); Input=getString1 (); if(Input.equals ("")) { Break; } reverser Thereverser=Newreverser (input); Output=Thereverser.dorev (); System.out.println ("Reversed:" +output); } } Public StaticString getString

value.Similarly, when an element of the RightMark position is greater than or equal to the base value, RightMark moves to the left one position to continue scanning, and the scan stops when the element of the RightMark position is less than the base value.After stopping the scan, we compare the size of the Leftmark and RightMark, if the Rightmark　　After we have put the datum values in the correct position, we see that the elements on the left side of the base value are smaller than the datum va

"Select Sort"The selection sort is based on a bubbling sort (Bubble sort) that has been improved: each visit process (pass) needs to be exchanged at most.Each visit process, to find the maximum value, when the end of the visit, the maximum value is exchanged to the correct position;Then continue to repeat the process in the remaining sublist until the n-1 visit is completed (n is the length of the list);At this point, the remaining elements in the list are automatically aligned to the correct po

= [] showing the same gender; Let len = this.list.length; while (len--) {if (This.list[len].gender = = = Gender) {Ret.push (this.list[len].name); }} return ret;} Example let people = new person ();p eople.save (' Mazey ', ' Male ');p eople.save (' John ', ' Male ');p eople.save (' Zero ', ' Male '); People.save (' July ', ' Male ');p eople.save (' Bob ', ' Male ');p eople.save (' Ada ', ' female ');p eople.save (' Cherrie ', ' female ');p eople.save (' Luna ', ' female ');p eople.save

This article illustrates the fast sequencing of data structures and algorithms implemented by Python. Share to everyone for your reference. The specific analysis is as follows: I. Overview Quick Sort is a sort of divide-and-conquer algorithm. The algorithm first selects a partitioning element (partition element, sometimes called a pivot), and then rearranges th

Note: This blog is my understanding of the data structure, many local understanding may not be appropriate, but also ask the reader to learn dialecticallyUnderstanding data structures from the macro levelMany times we have been working hard, but don't know why ...After a year of work, re-think of the university's data

First, insert sortWhat is insert sort: insert sort is to insert a value into an ordered data by size, and after inserting the value, the data is still in order.Time complexity for inserting sorting: The large O method is O (n^2). But more quickly than bubble sort and select sortTo insert a sort plot:　　　　　　　　Specific Java code: Public classInsertsort {int[] Array =NULL; @Test Public voidTestinsertsort () {ar

to the collection of elements that exist in relation to each other, and the relationships in the data structure mainly refer to neighboring relationships . The data structure includes three aspects: the logical structure, the storage structure and the operation of the data.1.6 Formal definition of data structureThe fo

Original: Lock-free data structure (LOCK-FREE data structures)One weeks ago, I wrote an article about the latch (latches) and spin lock (Spinlocks) in SQL Server. The 2 synchronization primitives (synchronization primitives) are used to protect shared data structures in SQL

One weeks ago, I wrote an article about the latch (latches) and spin lock (Spinlocks) in SQL Server. The 2 synchronization primitives (synchronization primitives) are used to protect shared data structures in SQL Server, such as pages in the cache pool (via a latch (latches)), and locks in the Lock Manager hash table (via a spin lock (Spinlock)). Next you will see more and more new synchronization primitive

heap sorting.8. Diagram A graph consists of a finite set V of a node and a set E of an edge. In order to distinguish it from the tree structure, the node is often called a vertex in the graph structure, and the edge is an ordered even pair of vertex. If there is an edge between two vertices, the two vertices are adjacent. The vertex direction can be divided into an undirected graph and a directed graph: The figure is a complex data structure with c

What is a data structure :The data structure is the way that the computer stores and organizes it.A data structure is a collection of elements that have one or more specific relationships to each othertypically, a well-chosen data structure can lead to higher operational or storage Efficiency.

1. What is the use of learning data structures? 2. Is it necessary to learn the algorithm? Reply content:Personally think data structure is one of the most important basic skills of programming! Learn the sequential table and linked list, you know, in the query operation of more programs, you should use the sequential table, and modify the operation of more prog

To make it easier for computers to serve us, we need to digitize all things in reality and store them in the computer, because there is a certain relationship between things in reality and things, so we need to study these relationships (forms of existence in the computer world and forms of existence in the real age ), that is to say, we need to study the logical structure in the data structure (several ways in which relations exist in the real world)

processed by a computer program.data element: is the basic unit of data, which is usually considered and processed as a whole in computer programs.A data item is an indivisible minimum unit of data. A data element can consist of several data items.data object: is a collecti

I. Linked listWhen learning the list of data structures, there are linked lists that differentiate between the leading nodes and the nodes that do not take the lead .At that time, after writing the basic operation algorithm of the link list of the lead node, I wrote the basic operation of the linked list without the lead node.The difference between finding a lead node is mainly in the 2