关于怎么在10万个手机号码中选择重复号码的问题(目前最高效的算法)

晚上看到有算法分享关于怎么在10万个手机号码中选择重复号码的问题。

刚好晚上有空，也写了一个算法。

 

Dictionary<int, int> dic = new Dictionary<int, int>();
            int count3 = 0;
            
            foreach (var item in mobileArray)
            {
                var hashCode = item.GetHashCode();
                int outInt = 0;

                if (dic.TryGetValue(hashCode, out outInt))
                {
                    if (outInt == 1)
                    {
                        count3++;
                        dic[hashCode] = 2;
                    }
                }
                else
                    dic[hashCode] = 1;

            }

 

有下面几点需要注意：

1. Dictionary的Key本身是hash，效率很高
2. 相同的字符串在.net实际上是同一个地址，所以GetHashCode是一样的。

效果：

欢迎各位高手弄出个更快的算法

 

所有代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace 手机号码重复算法
{
    unsafe class Program
    {
        static void Main(string[] args)
        {
            //示例数组，存放手机号
            string[] mobileArray = new string[100000];// { "13900001234", "13900001235", "13900001236", "13900001237", "13900001234" };

            for (int i = 0; i < 100000; i++)
            {
                mobileArray[i] = "1390000"
                    + (i.ToString().Length > 4 ? i.ToString().Substring(0, 4) : (i.ToString() + "0000").Substring(0, 4));
            }

            ////linq语句来实现【select mobile from tmpTable group by mobile having count(*)>1】的效果
            var selMobile = from n in mobileArray group n by n into g where g.Count() > 1 select g.Distinct();// select g;



            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
            sw.Reset();
            sw.Start();
            int count1 = 0;
            //通过两层循环输出重复的手机号
            foreach (var mobile in selMobile)
            {
                foreach (string multiMobile in mobile)
                {
                    count1++;
                    //Console.WriteLine(multiMobile);
                }
            }

            sw.Stop();

            Console.WriteLine("Linq共有重复号" + count1 + "耗时" + sw.ElapsedMilliseconds);

            TenNodeTree tree = new TenNodeTree();
            TenNodeTree tree2 = new TenNodeTree();

            sw.Reset();
            sw.Start();
            int count2 = 0;
            //mobileArray = new string[] { "13900001234", "13900001235", "13900001236", "13900001237", "13900001234", "13900001236" };

            foreach (var item in mobileArray)
            {
                fixed (char* no = item)
                {
                    if (!tree.Add(no, 11))
                    {
                        if (tree2.Add(no, 11))
                        {
                            count2++;
                        }
                    }
                }

            }

            sw.Stop();

            Console.WriteLine("十叉树共有重复号" + count1 + "耗时" + sw.ElapsedMilliseconds);



            sw.Restart();
            Dictionary<int, int> dic = new Dictionary<int, int>();
            int count3 = 0;
            
            foreach (var item in mobileArray)
            {
                var hashCode = item.GetHashCode();
                int outInt = 0;

                if (dic.TryGetValue(hashCode, out outInt))
                {
                    if (outInt == 1)
                    {
                        count3++;
                        dic[hashCode] = 2;
                    }
                }
                else
                    dic[hashCode] = 1;

            }

           

            sw.Stop();
            Console.WriteLine("hash计算共有重复号" + count3 + "耗时" + sw.ElapsedMilliseconds);

            Console.ReadLine();

        }

        class TenNodeTree
        {
            public TenNode Root = new TenNode();

            public bool Add(char* no, int len)
            {
                TenNode cnode = Root;
                bool isadd = false;

                for (int i = 0; i < len; i++)
                {
                    char k = *no;

                    if (cnode.Child[k - 48] == null)
                    {
                        isadd = true;
                        cnode.Child[k - 48] = new TenNode();
                    }
                    cnode = cnode.Child[k - 48];

                    no++;

                }

                return isadd;

            }

        }

        class TenNode
        {
            public TenNode[] Child = new TenNode[10];
        }


    }
}