C#实现KMP算法

/// <summary>
/// 串的模式匹配 KMP算法
/// </summary>
/// <param name="str"></param>
/// <param name="model"></param>
/// <param name="pos"></param>
/// <returns></returns>
private static int KmpMatch(char[] str, char[] model,int pos)
{
int loc = -1;
if (pos < 1 || pos > str.Length)
{
return loc;
}

int i = pos - 1;
int j = 0;
int[] next = GetNext(model);

while (i < str.Length && j < model.Length)
{
if (j == -1 || str[i] == model[j])
{
i++;
j++;
}
else
j = next[j];
}
if (j >= model.Length)
loc = i - model.Length;

return loc;
}

/// <summary>
/// 求next[]
/// </summary>
/// <param name="T"></param>
/// <returns></returns>
private static int[] GetNext(char[] T)
{
int[] next = new int[T.Length];
next[0] = -1;

int i = 0, j = -1;

while (i < T.Length - 1)
{
if (j == -1 || T[i] == T[j])
{
++i; ++j;
if (T[i] != T[j])
next[i] = j;
else
next[i] = next[j];
}
else
j = next[j];
}

return next;
}