CareerCup

Hey googler, could you please clarify the question... with Sample input and Sample output

/* 26-bit mask  i.e 1-bit for each character from 'a' to 'z' */

void FindRepeartedCharacters(char *S)
{
    if( S == NULL )
        return ;
    else
    {
        int len = strlen(S);
        int i=0;
        int MASK:26 = 0; // bit-filed

        while(i < len -1 )
        {
            if ( alpha(S[i] )
            {
                if( S[i] >= 'A' && S[i]<='Z')
                {
                    S[i] = lower(S[i]);
                }

                if( MASK & (1<< (S[i] - 'a')) )
                {
                    printf("\n %c is repeated", S[i]);
                }
                else
                {
                        MASK | =  1<< (S[i] - 'a') ;
                }
            }
            else
            {
                printf("\n wrong input ");
                exit(0);
            }
            i++;
        }

    }
}

/* 52-bit mask  i.e 2-bit for each character from 'a' to 'z' */
/* 0,1st bits for 'a'. 2,3rd bits for 'b' ... */
/* if two bits are 1 for a character , then character is repeated */

void FindRepeartedCharacters(char *S)
{
    if( S == NULL )
        return ;
    else
    {
        int len = strlen(S);
        int i=0;
        int MASK:52 = 0; // bit-filed

        while(i < len -1 )
        {
            if ( alpha(S[i] )
            {
                if( S[i] >= 'A' && S[i]<='Z')
                {
                    S[i] = lower(S[i]);
                }

                if( MASK & (1<< (S[i] - 'a')*2) )
                {
                     MASK | =  1<< ((S[i] - 'a')*2 + 1 ) ;
                }
                else
                {
                        MASK | =  1<< (S[i] - 'a')*2 ;
                }
            }
            else
            {
                printf("\n wrong input ");
                exit(0);
            }
            i++;
        }// end of while
        i=0;
        while(i<26)
        {
            if( (MASK & 1<<2*i) && (MASK & 1<<(2*i + 1) ) )
            {
                printf("\n %c is repeated \n", i + 'a' );
            }
        }


    }
}

If you find any bug in my code , please let me know

guys..question it nt put in a right way..the question is how to find the repeated elements in a string?

Suppose for exp: in the string "rajinikanth"..char 'i','a','n'... is repeated...using the mask as given above it can done..

Can someone pls clarify what the masking operation exactly does? How does it solve the problem of finding repeated characters???

find a repeated string is ok using bit mask but for a set of strings without changing the bit mask ?