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

public class StringCompute
{
  #region 私有變量
  /// <summary>
  /// 字符串1
  /// </summary>
  private char[] _ArrChar1;
  /// <summary>
  /// 字符串2
  /// </summary>
  private char[] _ArrChar2;
  /// <summary>
  /// 統(tǒng)計(jì)結(jié)果
  /// </summary>
  private Result _Result;
  /// <summary>
  /// 開始時(shí)間
  /// </summary>
  private DateTime _BeginTime;
  /// <summary>
  /// 結(jié)束時(shí)間
  /// </summary>
  private DateTime _EndTime;
  /// <summary>
  /// 計(jì)算次數(shù)
  /// </summary>
  private int _ComputeTimes;
  /// <summary>
  /// 算法矩陣
  /// </summary>
  private int[,] _Matrix;
  /// <summary>
  /// 矩陣列數(shù)
  /// </summary>
  private int _Column;
  /// <summary>
  /// 矩陣行數(shù)
  /// </summary>
  private int _Row;
  #endregion
  #region 屬性
  public Result ComputeResult
  {
    get { return _Result; }
  }
  #endregion
  #region 構(gòu)造函數(shù)
  public StringCompute(string str1, string str2)
  {
    this.StringComputeInit(str1, str2);
  }
  public StringCompute()
  {
  }
  #endregion
  #region 算法實(shí)現(xiàn)
  /// <summary>
  /// 初始化算法基本信息
  /// </summary>
  /// <param name="str1">字符串1</param>
  /// <param name="str2">字符串2</param>
  private void StringComputeInit(string str1, string str2)
  {
    _ArrChar1 = str1.ToCharArray();
    _ArrChar2 = str2.ToCharArray();
    _Result = new Result();
    _ComputeTimes = 0;
    _Row = _ArrChar1.Length + 1;
    _Column = _ArrChar2.Length + 1;
    _Matrix = new int[_Row, _Column];
  }
  /// <summary>
  /// 計(jì)算相似度
  /// </summary>
  public void Compute()
  {
    //開始時(shí)間
    _BeginTime = DateTime.Now;
    //初始化矩陣的第一行和第一列
    this.InitMatrix();
    int intCost = 0;
    for (int i = 1; i < _Row; i++)
    {
      for (int j = 1; j < _Column; j++)
      {
        if (_ArrChar1[i - 1] == _ArrChar2[j - 1])
        {
          intCost = 0;
        }
        else
        {
          intCost = 1;
        }
        //關(guān)鍵步驟，計(jì)算當(dāng)前位置值為左邊+1、上面+1、左上角+intCost中的最小值 
        //循環(huán)遍歷到最后_Matrix[_Row - 1, _Column - 1]即為兩個(gè)字符串的距離
        _Matrix[i, j] = this.Minimum(_Matrix[i - 1, j] + 1, _Matrix[i, j - 1] + 1, _Matrix[i - 1, j - 1] + intCost);
        _ComputeTimes++;
      }
    }
    //結(jié)束時(shí)間
    _EndTime = DateTime.Now;
    //相似率 移動(dòng)次數(shù)小于最長的字符串長度的20%算同一題
    int intLength = _Row > _Column ? _Row : _Column;

    _Result.Rate = (1 - (decimal)_Matrix[_Row - 1, _Column - 1] / intLength);
    _Result.UseTime = (_EndTime - _BeginTime).ToString();
    _Result.ComputeTimes = _ComputeTimes.ToString();
    _Result.Difference = _Matrix[_Row - 1, _Column - 1];
  }


  /// <summary>
  /// 計(jì)算相似度（不記錄比較時(shí)間）
  /// </summary>
  public void SpeedyCompute()
  {
    //開始時(shí)間
    //_BeginTime = DateTime.Now;
    //初始化矩陣的第一行和第一列
    this.InitMatrix();
    int intCost = 0;
    for (int i = 1; i < _Row; i++)
    {
      for (int j = 1; j < _Column; j++)
      {
        if (_ArrChar1[i - 1] == _ArrChar2[j - 1])
        {
          intCost = 0;
        }
        else
        {
          intCost = 1;
        }
        //關(guān)鍵步驟，計(jì)算當(dāng)前位置值為左邊+1、上面+1、左上角+intCost中的最小值 
        //循環(huán)遍歷到最后_Matrix[_Row - 1, _Column - 1]即為兩個(gè)字符串的距離
        _Matrix[i, j] = this.Minimum(_Matrix[i - 1, j] + 1, _Matrix[i, j - 1] + 1, _Matrix[i - 1, j - 1] + intCost);
        _ComputeTimes++;
      }
    }
    //結(jié)束時(shí)間
    //_EndTime = DateTime.Now;
    //相似率 移動(dòng)次數(shù)小于最長的字符串長度的20%算同一題
    int intLength = _Row > _Column ? _Row : _Column;

    _Result.Rate = (1 - (decimal)_Matrix[_Row - 1, _Column - 1] / intLength);
    // _Result.UseTime = (_EndTime - _BeginTime).ToString();
    _Result.ComputeTimes = _ComputeTimes.ToString();
    _Result.Difference = _Matrix[_Row - 1, _Column - 1];
  }
  /// <summary>
  /// 計(jì)算相似度
  /// </summary>
  /// <param name="str1">字符串1</param>
  /// <param name="str2">字符串2</param>
  public void Compute(string str1, string str2)
  {
    this.StringComputeInit(str1, str2);
    this.Compute();
  }

  /// <summary>
  /// 計(jì)算相似度
  /// </summary>
  /// <param name="str1">字符串1</param>
  /// <param name="str2">字符串2</param>
  public void SpeedyCompute(string str1, string str2)
  {
    this.StringComputeInit(str1, str2);
    this.SpeedyCompute();
  }
  /// <summary>
  /// 初始化矩陣的第一行和第一列
  /// </summary>
  private void InitMatrix()
  {
    for (int i = 0; i < _Column; i++)
    {
      _Matrix[0, i] = i;
    }
    for (int i = 0; i < _Row; i++)
    {
      _Matrix[i, 0] = i;
    }
  }
  /// <summary>
  /// 取三個(gè)數(shù)中的最小值
  /// </summary>
  /// <param name="First"></param>
  /// <param name="Second"></param>
  /// <param name="Third"></param>
  /// <returns></returns>
  private int Minimum(int First, int Second, int Third)
  {
    int intMin = First;
    if (Second < intMin)
    {
      intMin = Second;
    }
    if (Third < intMin)
    {
      intMin = Third;
    }
    return intMin;
  }
  #endregion
}
/// <summary>
/// 計(jì)算結(jié)果
/// </summary>
public struct Result
{
  /// <summary>
  /// 相似度
  /// </summary>
  public decimal Rate;
  /// <summary>
  /// 對(duì)比次數(shù)
  /// </summary>
  public string ComputeTimes;
  /// <summary>
  /// 使用時(shí)間
  /// </summary>
  public string UseTime;
  /// <summary>
  /// 差異
  /// </summary>
  public int Difference;
}

// 方式一
StringCompute stringcompute1 = new StringCompute();
stringcompute1.SpeedyCompute("對(duì)比字符一", "對(duì)比字符二");  // 計(jì)算相似度， 不記錄比較時(shí)間
decimal rate = stringcompute1.ComputeResult.Rate;     // 相似度百分之幾，完全匹配相似度為1

// 方式二
StringCompute stringcompute2 = new StringCompute();
stringcompute2.Compute();                 // 計(jì)算相似度， 記錄比較時(shí)間
string usetime = stringcompute2.ComputeResult.UseTime;   // 對(duì)比使用時(shí)間