sunday算法（有bug）不能count_sunday算法有问题-优快云博客

本文链接：https://blog.youkuaiyun.com/ministarler/article/details/12930865

本文介绍了一个算法实现，在给定的文本中查找特定字符串的出现位置，并统计其出现次数。通过逐步比较源字符串与目标字符串，算法能够高效地定位目标字符串在文本中的首次出现并返回其偏移量。

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//实现了 count，但是针对最后的 关键字不能计算在内
#include<stdio.h>
#include<string.h>

int ISFindTheCh(char * const target,char ch);

int IsMatch(char *const source,char * target);

int main()
{
	char string[] = "hellohello world!，worryhellow";
	char str[] ="wor";
    static int numWord = 0;
    static int count = 0;
    int Source_Lenth =(int) strlen(string);
	int Target_Lenth = (int) strlen(str);
    
    //while( count + Target_Lenth < Source_Lenth)
    while( count < Source_Lenth)
    {
        char *strterm;
        if(count == 0)
            strterm = string;
        else
            strterm = string +count+numWord*Target_Lenth;
        
        int offset = IsMatch(strterm,str);
        if (offset < 0)
        {
            printf("No Find '%s' again. \n",str);
            printf("the find num of the '%s' is %d.\n",str,numWord);
            
            return 0;
        }
        numWord +=1;
        count += offset;
        printf("Find '%s' in offset: %d \n",str,count);
    }
    
	
	
	return 1 ;
}

int ISFindTheCh(char * const target,char ch)
{
	char * p = strrchr(target,ch);//从后往前匹配的第一个字符
    if(p)
		return (int)(p - target);
	else
		return -1;
}

int IsMatch(char *const source,char * target)
{
	int Source_Lenth =(int) strlen(source);
	int Target_Lenth = (int)strlen(target);
	
	char *Sp = source;//源文件指针
	char *St = target;//目标文件指针
	char *SumP = source + Target_Lenth;
    //    if ((Source_Lenth - Target_Lenth) <0)
    //        return -1;
	
	int offset = -1;
	int count = 0;
	while(Source_Lenth  > Target_Lenth)
	{
		
		if(*Sp == *St)
		{
			Sp++;
			St++;
			Source_Lenth--;
			count++;
			if(count == Target_Lenth)
            {
                // printf("---Find '%s' in offset: %ld \n",target,Sp-source-count);
				return (int)(Sp-source-count);
                
                
            }
		}
		else
		{
		   	offset = ISFindTheCh(target,SumP[0]);
			if(offset == -1)
			{
				Sp = SumP +1 ;
                SumP = Sp + Target_Lenth;
			}
			else
			{
				Sp = SumP - offset;
				Source_Lenth += offset;
			}
			
			St = target;
			count = 0;
			Source_Lenth -= Target_Lenth ;
			
		}
        
	}
    // printf("No Find '%s' again. \n",target);
    return -1;
	
}


//不能计数count、
#include<stdio.h>
#include<string.h>


int ISFindTheCh(char * const target,char ch);


int IsMatch(char *const source,char * target);


int mian()
{
char string[] = "hello world!";
char str[] ="str";
int is;
if((is = IsMatch(string,str)))
printf("Find '%s' in offset: %d \n",str,is);

return 1 ;
}


int ISFindTheCh(char * const target,char ch)
{
char * p = strrchr(target,ch);//从后往前匹配的第一个字符
    if(p)
return p - target;
else
return -1;
}


int IsMatch(char *const source,char * target)
{
int Source_Lenth = strlen(source);
int Target_Lenth = strlen(target);

char *Sp = source;//源文件指针
char *St = target;//目标文件指针
char *SumP = source + Target_Lenth;

int offset = -1;
int count = 0;
while(Source_Lenth > 0)
{

if(*Sp == *St)
{
Sp++;
St++;
Source_Lenth--;
count++;
if(count == Target_Lenth)
return Sp-source-count;
}
else
{
  offset = ISFindTheCh(source,SumP[0]);
if(offset == -1)
{
Sp = SumP +1 ;
                SumP = Sp + Target_Lenth;
}
else
{
Sp = SumP - offset;
Source_Lenth += offset;
}

St = target;
count = 0;
Source_Lenth -= Target_Lenth ;

}

}
   return -1; 

}