udemy data structures and algorithms

(self) self.engine.accept (visitor) self.body.accept (Visito R) forWheelinchself.wheels:wheel.accept (visitor)#This is our visitor, and every change is here .classPrintvisitor:defVisitwheel (self, Wheel):Print "Visiting"+wheel.name+"Wheel" defVisitengine (self, Engine):Print "Visiting engine" defvisitbody (self, body):Print "Visiting Body" defVisitcar (self, car):Print "Visiting Car"if __name__=='__main__': Car=Car () visitor=printvisitor () car.accept (visitor)Learn some Python basics

Package Com.js.ai.modules.pointwall.testxfz;class ordarray{private long[] a;private int nelems;public OrdArray (int max ) {a=new long[max];nelems=0;} public int size () {return nelems;} Insert method public void Insert (Long value) {int j;for (j=0;j　　Data structures and algorithms: the dichotomy Demo

True Second, collections. Ordereddict: Dictionary with OrderOrdereddict internally maintains a doubly linked list to record the order in which key values are inserted, update the key value does not affect the original order, insert key value is inserted at the end, so its memory consumption is twice times the normal dictionary ,From collections Import ORDEREDDICTD = Ordereddict () d[' a '] = 1d[' c '] = 3d[' b '] = 2print (d, D.items ()) Ordereddict (' A ', 1), (' C ', 3)

-set receives a tree height effect and is less efficient. Therefore, there are two kinds of improved heuristic algorithms.The first is to merge by rank, and for each node to record his height, change the father of the smaller node to the larger one. If both sides are equal, select one as the father, and the rank of the root node plus one.The second is path compression, and each time the find-set is called, the father of the node found on the path is changed directly to the root node.1make-SET (x

1. The principle of hill sorting2. Code implementationdefShell_sort (alist): N=Len (alist)#Initial StepGap = N/2 whileGap >0:#Insert Sort by step forIinchRange (Gap, N): J=I#Insert Sort whileJ>=gap andALIST[J-GAP] >Alist[j]: alist[j-GAP], alist[j] = alist[j], alist[j-Gap] J-=Gap#get a new step sizeGap = GAP/2alist= [54,26,93,17,77,31,44,55,20]shell_sort (alist)Print(alist)Attention:(1) Hill sort uses the idea of splitting up and merging, splitting apart3. Complexity of TimeOp

List operation code is small but more error-prone, is more suitable for the interview place. Code implementation /** * Source Name: Mylinklist.java * Date: 2014-09-05 * program function: Java list operation * Copyright: [emailprotected] * A2bgeek */import Java.util.Sta Ck;public class Mylinklist {class Linknode"Data structures and Algorithms" Java l

node is now Point to the head of the now node's next pointer; Set the now node to the head of the new rollover completion node header now; Point to head now, and so on, the next pointer to the previous node of the now node. 3. Two points search common scenes Finding a number in an ordered sequence; For example, given an array of arr, determine if the integer m is in arr (Train of thought: Determine the size of the mid-to-m re

; J ) {System.out.print (A[j]+ " "); } System.out.println (""); } //Bubble Sort Public voidBubblesort () {intOut , in; for(out = nElems-1, out > 1; out--) { for(in = 0; in ) { if(A[in] > a[in + 1]) {swap (in,+ 1); } } } } //Insert Sort Public voidInsertionsort () {intin, out; //Out are dividing line for(out = 1; out ) { //Remove marked item Longtemp =A[out]; //start shifts at outin =Out ; wh

The implementation of the dictionary// 字典类function Dictionary () { this.add = add; this.dataStore = new Array(); this.find = find; this.remove = remove; this.showAll = showAll; this.count = count; this.clear = clear;}function add (key, value) { this.dataStore[key] = value;}function find (key) { return this.dataStore[key];}function remove (key) { delete this.dataStore[key];}function showAll () { let datakeys = Array.prototype.slice.call(Object.keys(this.dataStore)

node1.next = node3; node3.previous = node1; node3.next = node2; node2.previous = node3; node2.next = node4; node4.previous = node2; }};DList.prototype.advance = function (n, item) { let currNode = this.find(item); while (n--) { this.goPrevious(currNode); }};// 示例let names = new DList();names.insert('Mazey', 'head');names.insert('Cherrie', 'Mazey');names.insert('John', 'Cherrie');names.insert('Luna', 'John');names.insert('Ada', 'Luna'

efficiency: In a merge sort, the maximum value of this secondary storage space is not more than N, so the spatial complexity of the merge algorithm is θ (n) in order to combine the sub-sequences to use additional storage space.Time efficiency: The merging algorithm is a typical divide-and-conquer algorithm with a time complexity of 0 (n log n).　3. Algorithm examplesMergesort.javaPackage Com.test.sort.merge;public class MergeSort {/** * @param args */public static void main (string[] args) {//TO

" definition of algorithmic time complexity"At the time of the algorithm analysis, the total number of executions of the statement T (N) is a function of the problem size n, which then analyzes the change of T (n) with N and determines the order of magnitude of T (N). The time complexity of the algorithm, which is the time measurement of the algorithm, is recorded as: T (n) = O (f (n)). It indicates that with the increase of the problem size n, the growth rate of the algorithm execution time is

]; while (end>start) { while (end>startarrys[key)//If there is nothing smaller than the key value, compare next until there is a smaller swap position than the key value, And then compare it back to the past End--; if (arrys[end]) { arrys[end]; arrys[arrys[start]; arrys[tmp; } while (end>startarrys[start]) Start+ +; if (arrys[key) {

Bucket sortBarrel sequencing has been used since the 1956, and the basic idea of the algorithm is proposed by E.J.ISSAC and R.c.singleton.This algorithm is like having 11 barrels, numbered from 0~10. Each occurrence of a number, in the corresponding number of buckets put aA little flag, and then just count the few small flags in each bucket OK. For example, there are 1 small flags in bucket 2nd, indicating2 appeared once, and in the 3rd barrels there were 1 small flags, indicating that 3 appeare

can put in *, in Put +, that is abc*+.A * (b+c) turn suffix:Read a, read *, later found (can not be placed *, (B+C * Priority High, read, followed by), can be changed to bc+, and a * together, that is abc+*.This is a queue, but the structure to use is the stack, because it comes in. The arithmetic here does not have to be pressed into the stack, directly output.a+b-c Turn suffix:Direct output A, read +, stack empty press into the stack, then output B, stack non-empty, pop +, read to-,+ priority

and J to point to the leftmost and rightmost of the sequence, respectively. At first, the variable I points to the leftmost part of the sequence, which is the number 6, and J points to the far right of the sequence, pointing to the number 8, as shown inFirst J moves from right to left, so long as it finds a number smaller than 6, it stops, and J is in the 5 position. I then start from left to right, as long as I find a number greater than 6 to stop, so it to the position of 7This is where the t

Using system;using system.collections.generic;using system.linq;using system.text;using System.Threading.Tasks; Namespace selectsort{class Program {static void Main (string[] args) {int[] Arry = {1, 4, 5,6,2,9,0,8,3,10}; Selectesort (Arry, Arry. Length); for (int i = 0; i Because of the two for loops, the time complexity is O (n^2), which is a simple but very slow sort.Selection and sequencing of algorithms and

Today we will talk about how to calculate the complexity of time.The concept of Time complexity: (Baidu version)The same problem can be solved by different algorithms, and the quality of an algorithm will affect the efficiency of the algorithm and even the program. The purpose of the algorithm analysis is to select the suitable algorithm and the improved algorithm.In computer science, the time complexity of an algorithm is a function that quantitative

of its parent node.This situation is the most difficult to solve, because no matter how it can not be adjusted with a discoloration or a single rotation, this situation is usually used in conjunction with Case 5, first of all, the parent node of the insertion node is the axis left-handed.Before adjustmentAfter adjustmentCase 5: The parent node of the current node is red, the Uncle node is black, and the current node is the left child node of its parent node.In case 4, the parent node of the ins

element.Filter (): Takes a function as a parameter, returning all elements that enable the function to return true.4. Two-dimensional and multidimensional arraysThere is no two-dimensional array in JavaScript, but you can implement a two-dimensional array by inserting array elements into the array.var twod = []; var rows = 5; for (var i = 0; i i) {= [];}With regard to how to create a two-dimensional array, a best practice is mentioned in the book, which is a 64-page example of javascript:th