JeffreyZhao

// As we all know, the generic List<T> class in .NET doesn't 
// have a RemoveMultiple method. Could you implement it for me?
// Say the elements are kept in the _items field, which is an
// array of type T. Also, use _count to keep the current number
// of elements.
// PS: You can compare two items with "==" operator.

namespace System.Collections.Generic
{
    public class List<T>

JeffreyZhao

using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using BenchmarkDotNet.Attributes;

namespace Dict
{
    public class DictionaryPerf
    {
        private Dictionary<int, int> _original;

JeffreyZhao

打印表头

小明正在用JavaScript写一个日志分析程序。该程序会将日志转化为CSV文件，以便在Excel等应用中加载为一个表格。现在他在生成表头上遇到了困难。

他需要实现如下一个方法：

function printLine(array) {
    console.log(array.join(","));
}

JeffreyZhao

namespace SimpleConsole
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    class Program
    {
        static void Main()

JeffreyZhao

// Please write an sequence list implements the interface with the required
// time complexity described in the comments. The users can add the same
// element as many times as they want, but it doesn't support the null item.
// You can use any types in .NET BCL but cannot use any 3rd party libraries.
// PS: You don't need to consider the multi-threaded environment.
interface IMyList<T> : IEnumerable<T>
{
    // O(1)
    // Add an item at the beginning of the list.
    void AddFirst(T item);

JeffreyZhao

///////////////////////////////////////////////////////
// Talk is cheap. Show me the code. - Linus Torvalds
///////////////////////////////////////////////////////

public abstract class CalculatorBase : IDisposable {
    
    protected void StartCore() {
        // ...
    }
    

JeffreyZhao

namespace HashTableDict
{
    using System.Collections;
    using System.Collections.Generic;

    public class Hashtable<TKey, TValue> : IDictionary<TKey, TValue>
        where TKey : class
        where TValue : class
    {
        private readonly Hashtable _ht = new Hashtable();

JeffreyZhao

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Dynamic;
using System.Xml.Linq;
using System.Xml;
using System.Threading;
using System.Threading.Tasks;
using System.Diagnostics;

JeffreyZhao

// 其实这题可以写的很简单，它的关键根本不是CAS操作。

// 使用一个标志（flag也好，status判断也罢）来避免Start和Dispose重入是很容易
// 想到的手段，很多同学也这么做了。大部分同学遇到的问题是：假如StartCore已经
// 启动，那么如何让Dispose方法等待其完成。有些同学用while (true)，有些同学用
// 锁，但都避免不了让Dispose线程等待Start线程。

// 这里“避免等待”的关键在于要跳出思维界限：谁说DisposeCore方法一定要在Dispose
// 方法里执行的？我们就不能在Start里销毁对象吗？

JeffreyZhao

struct MyKey {
    private readonly int _a;
    private readonly int _b;
    
    public MyKey(int a, int b) {
        _a = a;
        _b = b;
    }
}