Chapter 5(串)
阿新 • • 發佈：2018-07-18
keyword 字符 abs comment 圖片 mode class readonly include 
1.kmp
1.kmpx100 1#include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> void get_nextval(char *str,int *nextval) { int i,j; i = 0; j = -1; nextval[0] = -1; int len = strlen(str); while(i < len) { if(j==-1 || str[j]==str[i])//str[i]表示後綴的單個字符，str[j]表示前綴的單個字符 { ++i; ++j; if(str[i] != str[j]) //若當前字符與前綴字符不同，則當前的j為nextvale在i位置的值 { nextval[i] = j; } else //否則將前綴字符的nextval值賦給後綴字符的nextval { nextval[i] = nextval[j]; } } else { j = nextval[j];//若字符不同，則j值回溯 } } } void get_next(char *str,int *next) { int i,j; i = 0; j = -1; next[0] = -1; int len = strlen(str); while(i < len) { if(j==-1 || str[i]==str[j]) { ++i; ++j; next[i] = j; } else { j = next[j]; } } } int Index_KMP(char *strF,char *strS,int pos) { int i = pos; int j = 0;//字串中當前位置下標值 int next[255]; get_nextval(strS,next); int lenF = strlen(strF); int lenS = strlen(strS); while(i < lenF && j < lenS) //若i小於lenF且j小於lenS,循環繼續 { if(j == -1 || strF[i]==strS[j])//兩字符相等或者j為-1則繼續 { ++i; ++j; } else { j = next[j];//j回退合適的位置，i不變 } } if(j >= lenS)return i-lenS;//必須要由j使循環退出才說明找到了這個子串的位置 else return 0; } int main() { char *strF = "abcdecdefg"; char *strS = "defg"; printf("%d \n",Index_KMP(strF,strS,0)); return 0; }
void get_nextval(char *str,int *nextval)9{10 int i,j;11 i = 0;12 j = -1;13 nextval[0] = -1;14 int len = strlen(str);17 while(i < len) 18 {19 if(j==-1 || str[j 20 {21 ++i;22 ++j;23 if(str[i] != str[j]) //若當前字符與前綴字符不同，則當前的j為nextvale在i位置的值24 {25 nextval[i] = j;26 }27 else //否則將前綴字符的nextval值賦給後綴字符的nextval28 {29 30 }31 }32 else33 {34 j = nextval[j];//若字符不同，則j值回溯35 }36 }37}38void get_next(char *str,int *next)41{42 int i,j;43 i = 0;44 j = -1;45 next[0] = -1;46 int len = strlen(str);48 while(i < len)49 {50 if(j==-1 || str[i]==str[j])51 {52 ++i;53 ++j;54 next[i] = j;55 }56 else57 {58 j = next[j];59 }60 }61}62int Index_KMP(char *strF,char *strS,int pos)66{67 int i = pos;68 int j = 0;//字串中當前位置下標值70 int next[255];71 get_nextval(strS,next);72 73 int lenF = strlen(strF);74 int lenS = strlen(strS);75 while(i < lenF && j < lenS) //若i小於lenF且j小於lenS,循環繼續76 {77 if(j == -1 || strF[i]==strS[j])//兩字符相等或者j為-1則繼續78 {79 ++i;80 ++j;81 }82 else83 {84 j = next[j];//j回退合適的位置，i不變85 }86 }87 if(j >= lenS)return i-lenS;//必須要由j使循環退出才說明找到了這個子串的位置89 else return 0;90}91int main()95{96 char *strF = "abcdecdefg";97 char *strS = "defg";98 printf("%d \n",Index_KMP(strF,strS,0));99 return 0;100}附件列表
Chapter 5(串)