kmp演算法求解next值

void GetNextVal(const char* str, vector<int>& vec)<br />{<br />assert(str != NULL);<br />if (str != NULL)<br />{<br />int iLen = strlen(str);<br />vec.resize(iLen, -1);<br />int i = 0;<br />int j = -1;<br />if (iLen > 0)<br />{<br />vec[i] = j;<br />}<br />while (i < iLen - 1)<br />{<br />if (j == -1 || *(str + j) == *(str + i))<br />{<br />i++;<br />j++;<br />if (*(str + j) == *(str + i))<br />{<br />vec[i] = vec[j];<br />}<br />else<br />{<br />vec[i] = j;<br />}<br />}<br />else<br />{<br />j = vec[j];<br />}<br />}<br />}<br />}