kmp.cpp

自己写的数据结构代码

#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>
#define MAXSTRLEN 10000
typedef unsigned char SString[MAXSTRLEN+1];

void get_next(SString T,int next[])
{
	int i=1,j=0;
	next[1]=0;
	while(i<T[0])
	{
		if(j==0 || T[i]==T[j])
		{
			++i;
			++j;
			next[i]=j;
		}
		else  j=next[j];
	}
}

int index_KMP(SString S,SString T)
{
	int i=1,j=1;
	int next[MAXSTRLEN+1];
	get_next(T,next);
	while(i<=S[0] && j<=T[0])
	{
		if(j==0 || S[i]==T[j])
		{
			++i;
			++j;
		}
		else  j=next[j];
	}
	if(j>T[0])  return i-T[0];
	else        return 0;
}

int main()
{
	SString T,S;
	int n,i,j;
	char ch;
	int pos;
	scanf("%d",&n);
	ch=getchar();
	for(j=1;j<=n;j++)
	{
		ch=getchar();
		for(i=1;i<=MAXSTRLEN && (ch!='\n');i++)
		{
			S[i]=ch;
			ch=getchar();
		}
		S[0]=i-1;
		ch=getchar();
		for(i=1;i<=MAXSTRLEN && (ch!='\n');i++)
		{
			T[i]=ch;
			ch=getchar();
		}
		T[0]=i-1;
		pos=index_KMP(S,T);
		printf("%d\n",pos);
	}
	return 0;
}