数据结构 病毒dna匹配案例实现

#define _CRT_SECURE_NO_WARNINGS 
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<Windows.h>
#include<stddef.h>
#define MAX 100  

int BF_Find (char * str ,char * shortstr)
{
	int i;
	int j;
	int shortstrlength  = strlen(shortstr );
	//shortstr 字符串
	char  * buffer = malloc(sizeof(char )* (shortstrlength * 2 ) +1 );
	//最后一位存储'\0';
	buffer[shortstrlength * 2 ] = '\0';

	memcpy(buffer, shortstr, shortstrlength);
	memcpy(buffer + shortstrlength, shortstr, shortstrlength);
	//填充2倍
	printf("%s\n", buffer );

	char *  shortstrbuffer  = malloc( (sizeof (char) * shortstrlength ) +1 );
	//最后一位存储'\0符号

	memcpy(shortstrbuffer, buffer, shortstrlength);

	shortstrbuffer[shortstrlength] = '\0';
	
	printf("%s\n", shortstrbuffer);
	int x = 0; 
	while ( x < shortstrlength)
	{
		//复位
		i = 1;
		j = 1;
		//内层循环 查找一个字符串有没有 
		// 长字符串           //短字符串 
		while (str[i - 1] && shortstrbuffer[j - 1])
		{
			if (str[i - 1] == shortstrbuffer[j - 1])
			{
				i++;
				j++;
			}
			else
			{
				i = i - j + 2;
				j = 1;
			}
		}
		if (j > shortstrlength)
		{
			//找到 直接返回
			free(buffer);
			buffer = NULL;
			free(shortstrbuffer);
			shortstrbuffer = NULL;
			printf("free_1 : 释放成功 buffer shortstrbuffer \n");
			return i - j;
		}
		x++;
		memcpy(shortstrbuffer , buffer+x , shortstrlength);
	}


	if(j <=shortstrlength)
	{
		free(buffer);
		buffer = NULL;

		free(shortstrbuffer);
		shortstrbuffer = NULL;
		printf("free_2 : 释放成功 buffer shortstrbuffer \n");
		return  0; 
	}
}

int main()
{

	char* lengthstr = "assdwkiiojnksdiknsdsk";
	char* shortstr = "jiio";
	// jiio iioj ioji ojii 

	printf("查找 :下标是 %d\n", BF_Find(lengthstr, shortstr));

	system("pause");
	return 0;
}