Improved KMP pattern matching algorithm

Looking at the approximate steps of the algorithm, and then each one to prove the correctness of each step, the comments write some understanding.

This is not a fresh approach, just feel that the program is very delicate, repeated use of mathematical induction method.

It makes me feel fresh.

1 /*2 Next[i] Storage: match[i] mismatch, orig in the corresponding position will match the value3 According to KMP's thought,4 That is, the prefix of the longest and the same suffix in the 1 to i-1 substring the last item5 and this one is different from match[i]6                  7 if no prefix string exists but the first item differs from the I key, the value is 1. 8 If there is no prefix string and the first item is the same as I, the value is 0 and the J moves backward one position. 9 */Ten#include <stdio.h> One intMainvoid) A  { -      Charorig[ -],match[ -]; -     intnexterval[ -],next[ -],lengthorig,lengthmatch; the      for(lengthorig=1;; lengthorig++){ -         Charch; -scanf"%c",&ch); -         if(ch=='\ n'|| ch==' '){ +lengthorig--; -              Break;  +         } Aorig[lengthorig]=ch; at     } -      for(lengthmatch=1;; lengthmatch++){ -         Charch; -scanf"%c",&ch); -         if(ch=='\ n'|| ch==' '){ -lengthmatch--; in              Break; -         } tomatch[lengthmatch]=ch; +     } -next[1]=0;  thenext[2]=1; *      for(intI=3; i<=lengthmatch+1; i++) {//Next store the object that will match if I bit does not match $         intk=i-1;//that is, the last number of the longest prefix in 1 to i-1Panax Notoginseng          while(1){                      -             if(k==1){ thenext[i]=1; +                  Break; A             } the             if(match[i-1]==Match[next[k]]) { +next[i]=next[k]+1;  -                  Break; $             } $K=NEXT[K];//If you cannot prolong the formation of a substring next[k]+1 -}//and there is a substring of M, that substring must be a substring of the previous substring -     } the      for(intI=2; i<=lengthmatch+1; i++) {//if I!=0,match[next[i]] and match[i] must be different -         if(Match[i]==match[next[i]])//if Match[i]==match[next[i]]WuyiNext[i]=next[next[i]];//already have match[next[i]]!=match[next[next[i] ] the}//must have match[i]!=match[next[next[i] ] -     intI=1, j=1, total=0; Wu      while(1){//The item in front of I at the end of the while is already matched to the J front, and all previous matches have been tried -         if(i==lengthmatch+1){     About++Total ; $I=Next[i]; -             Continue;  -}//i-1 a successful match at the head -         if(j==lengthorig+1) Break; A         //when J-1 has i-1 to the end, the length limit of orig cannot match. +         if(i==0){ the++j,++i; -             Continue; $}//The first item does not match up with the back consideration of one the         if(Match[i]==orig[j]) ++i,++J; the         ElseI=Next[i]; the     } theprintf"They is match for%d times.", total); -}

Improved KMP pattern matching algorithm