[005] unique_sub_string

[Description] Given a string, find the largest unique substring.

e.g.　　str[] = "asdfghjkkjhgf";

　　　  sub[] = "asd";

[Thought] create an auxiliary space 'record[256]' to record the appearence of characters. O(n)

[Implementation] C code:

#include<stdio.h>

int uniqueSubStr(const char str[], char unique[])
{
        int record[256]={0};
        int i,len=0;
        for(i=0;str[i]!='\0';i++)
        {
                if(0==record[str[i]])
                {
                        record[str[i]]=1;
                        len++;
                        unique[len-1]=str[i];
                }
                else
                {
                        continue;
                }
        }
        unique[len]='\0';
        return len;
}

int main()
{
        char str[]="asdfjlkdfghjc";
        int size=sizeof(str);
        char unique[size];
        int i;

        printf("Initial string:\n");
        for(i=0;str[i]!='\0';i++)
        {
                printf("%c",str[i]);
        }
        printf("\nThe lagest length of unique substring is: %d\n", uniqueSubStr(str,unique));
        printf("The unique substring is:\n");
        for(i=0;unique[i]!='\0';i++)
        {
                printf("%c",unique[i]);
        }
        printf("\n");
        return 0;
}