C++ 实现KMP字符串匹配算法

int KMP(char * t, char * p)
{
  int i = 0;
  int j = 0;
  int* pNext = new int[(int)strlen(p)]{-1};
  GetNext(p,pNext);
  while (i < (int)strlen(t) && j < (int)strlen(p))
  {
    if (j == -1 || t[i] == p[j])
    {
      i++;
      j++;
    }
    else
      j = pNext[j];
  }
  if (j == strlen(p))
    return i - j;
  else
    return -1;
}

void GetNext(char * p, int * next)
{
  next[0] = -1;
  int i = 0, j = -1;
  while (i < (int)strlen(p))
  {
    if (j == -1 || p[i] == p[j])
    {
      ++i;
      ++j;
      next[i] = j;
    }
    else
      j = next[j];
  }
}