KMP algorithm (detailed next[n of strings)

How to find the pattern value of a string Next[n]

(1)next[0]=-1 meaning: The pattern value of the first character of any string is set to -1.

(2)next[j]=-1 meaning: The character of the pattern string T labeled J , if with the first character

The 1-k characters in front of J and the beginning of the 1-k

characters (or equal but t[k]==t[j]) (1≤k<j).

such as:t= "Abcabcad" is next[6]=-1, because t[3]=t[6]

(3)next[j]=k meaning: The character of the pattern string T is labeled J , if the front K of J

The characters are equal to the first K characters, and t[j]! = T[k] (1≤k<j).

IE t[0]t[1]t[2]... t[k-1]== t[j-k]t[j-k+1]t[j-k+2] ... T[J-1]

and t[j]! = t[k]. (1≤k<j);

(4) next[j]=0 meaning: In addition to (1) (2) (3) other circumstances.

#include <iostream.h>//#include <string.h> void get_nextval (const char *t, int next[]) {//Ask the next function of the pattern string T       Value and deposit the array next.       Int j = 0, k =-1;       Next[0] =-1; while (t[j]! = ' + ') {if (k = =-1 | |                     T[J] = = T[k]) {++j; ++k;                     if (T[j]!=t[k]) next[j] = k;              else next[j] = next[k];       } else K = next[k];       }//Here is my Add display section for (int i=0;i<j;i++) {cout<<next[i]<<endl;   } Cout<<endl;} int KMP (const char *text,const char* Pattern) {if (! Text| |!  pattern| |  pattern[0]== ' | |       text[0]== ' + ') return-1;//null pointer or empty string, return-1.       int len=0;       const char * c=pattern;         while (*c++!= ') {++len; } int *neXt=new int[len+1];       Get_nextval (Pattern,next);//Find the next function value of Pattern int index=0,i=0,j=0;                     while (text[i]!= ' && pattern[j]!= ') {if (text[i]== Pattern[j]) {                      ++i;              ++j;                     } else {index + = J-next[j];                            if (next[j]!=-1) j=next[j];//mode string move right else {                            j=0;                     ++i;       }}} delete []next;      if (pattern[j]== ') return index;//match success Else return-1;       }int Main () {char* text= "babadcadcaaaaa";               Char*pattern= "Adcad";       COUT&LT;&LT;KMP (Text,pattern) <<endl; return 0;}

KMP algorithm (detailed next[n of strings)