C字串相似度計算
阿新 • • 發佈：2019-02-09
#region 計算相似度
/// <summary>
/// 取最小的一位數
/// </summary>
/// <param name="first"></param>
/// <param name="second"></param>
/// <param name="third"></param>
/// <returns></returns>
public static int LowerOfThree(int first, int second, int third)
{
int min = first;
if (second < min)
min = second;
if (third < min)
min = third;
return min;
}
public static int Levenshtein_Distance(string str1, string str2)
{
int[,] Matrix;
int n = str1.Length;
int m = str2.Length;
int temp = 0;
char ch1;
char ch2;
int i = 0;
int j = 0;
if (n == 0)
{
return m;
}
if (m == 0)
{
return n;
}
Matrix = new int[n + 1, m + 1];
for (i = 0; i <= n; i++)
{
//初始化第一列
Matrix[i, 0] = i;
}
for (j = 0; j <= m; j++)
{
//初始化第一行
Matrix[0, j] = j;
}
for (i = 1; i <= n; i++)
{
ch1 = str1[i - 1];
for (j = 1; j <= m; j++)
{
ch2 = str2[j - 1];
if (ch1.Equals(ch2))
{
temp = 0;
}
else
{
temp = 1;
}
Matrix[i, j] = LowerOfThree(Matrix[i - 1, j] + 1, Matrix[i, j - 1] + 1, Matrix[i - 1, j - 1] + temp);
}
}
for (i = 0; i <= n; i++)
{
for (j = 0; j <= m; j++)
{
Console.Write(" {0} ", Matrix[i, j]);
}
Console.WriteLine("");
}
return Matrix[n, m];
}
/// <summary>
/// 計算字串相似度
/// </summary>
/// <param name="str1"></param>
/// <param name="str2"></param>
/// <returns></returns>
public static decimal LevenshteinDistancePercent(string str1, string str2)
{
int maxLenth = str1.Length > str2.Length ? str1.Length : str2.Length;
int val = Levenshtein_Distance(str1, str2);
return 1 - (decimal)val / maxLenth;
}
#endregion