kmp算法--求字符串子串--《数据结构》严蔚敏

来源：互联网发布：弹珠枪在淘宝上怎么搜编辑：程序博客网时间：2024/06/06 00:46

// exam1.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <iostream>using namespace std;void get_next(int* &next,char* s){int j=0;int i=1;int len=strlen(s);next=(int*)malloc(len*sizeof(int));memset(next,0,len*sizeof(int));while(s[i]!='\0'){if(s[j]==s[i]){i++;j++;if(s[i]!=s[j]){next[i]=j;}else{next[i]=next[j];}}else{if(j==0){i++;}j=next[j];}}}int kmp(int* next,char* s,char* m){int i=0,j=0;while(s[i]!='\0'){if(m[j]=='\0'){break;}if(s[i]==m[j]){i++;j++;}else{if(j==0){i++;}j=next[j];}}return i-strlen(m);}int main(void){int len,*next;char *s="acabaabaabcacaabc";char *m="abaabcac";len=strlen(m);get_next(next,m);int loc=kmp(next,s,m);/*for(int i=0;i<len;i++){cout<<next[i]<<endl;}*/cout<<loc<<endl;system("pause");return 0;}

code2

#include "stdafx.h"#include <iostream>#include <string>#include <stack>using namespace std;void getNext(char* s,int* &next){<span style="white-space:pre"></span>next=new int[strlen(s)];<span style="white-space:pre"></span>memset(next,0,strlen(s)*sizeof(int));<span style="white-space:pre"></span>int i=0;<span style="white-space:pre"></span>int j=-1;<span style="white-space:pre"></span>next[0]=-1;<span style="white-space:pre"></span>while(i<strlen(s))<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if(j==-1 || s[i]==s[j])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>i++;<span style="white-space:pre"></span>j++;<span style="white-space:pre"></span>if(s[i]==s[j])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>next[i]=next[j];<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>next[i]=j;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>j=next[j];<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}}void kmp(char* s,char* t,int* next){<span style="white-space:pre"></span>int i=0;<span style="white-space:pre"></span>int j=0;<span style="white-space:pre"></span><span style="white-space:pre"></span>int len1=strlen(s);<span style="white-space:pre"></span>int len2=strlen(t);<span style="white-space:pre"></span>while(i<len1 && j<len2)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if(j==-1 || s[i]==t[j])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>i++;<span style="white-space:pre"></span>j++;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>j=next[j];<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>if(j==strlen(t))<span style="white-space:pre"></span>{<span style="white-space:pre"></span>cout<<s+i-strlen(t)<<endl;<span style="white-space:pre"></span>}}int main(void){<span style="white-space:pre"></span>char* s="acabaabaabcacaabc";<span style="white-space:pre"></span>char* t="abaabcac";<span style="white-space:pre"></span>int* next;<span style="white-space:pre"></span>getNext(t,next);<span style="white-space:pre"></span>kmp(s,t,next);<span style="white-space:pre"></span>system("pause");<span style="white-space:pre"></span>return 0;}

0 0