CareerCup

1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20

We know that we will delete 5, 10 and 15 in this case. So, for the block from index 6-9 will be shifted left 1. block index 11-14 will shift over by 2. 16-19 will shift over by 3. Here we see a pattern. Because of continuous shifts, each block of numbers not divisible by 5 will shift left one more than the last block.

So, something like the following:

public void editBytes(byte[] arr) {
	

	int leftShiftAmount = 0;
	int i = 5;

	for (i = 5; i < arr.length; i+=5) {

		memmove(arr[i] - leftShiftAmount, arr[i + 1], sizeof(byte)*4);
		leftShiftAmount++;
	}

	int clearIndex = i - 5 - leftShiftAmount + 4;

	for (clearIndex = i - 5 - leftShiftAmount + 4; clearIndex < arr.length; clearIndex++) {//clear the garbage at the end, or you can just truncate up to this point


		arr[clearIndex] = 0;
	}

}

fnDefrag(string file)
{
	using (var stream = File.Open(file, FileMode.Open))
	{
		byte[] barry=new byte[1];
		int current=0;
		int pivot=0;
		while(current<(stream.length-1))
		{
			stream.position=current;
			if((current+1)%5==0)
			{
				current++;
			}
			if(current!=pivot)
			{
				stream.read(barry,current,1);
				stream.write(barry,pivot,1);
			}
			pivot++;	
			current++;
		}
		stream.SetLength=pivot;
	}
}

int main(int argc, char* argv[])
{
    FILE *fp_read, *fp_write;
    int counter = 1, i = 0;
    char ch;

    fp_read = fopen("input_file.txt", "r");
    fp_write = fopen("input_file.txt", "r+");

    if(!fp_read || !fp_write)
    {
        printf("File not present\n");
        exit(1);
    }

    fseek(fp_read, 0, SEEK_END);
    int size = ftell(fp_read);
    printf("Size = %d\n", size);
    fseek(fp_read, 0, SEEK_SET);

    while(counter < size)
    {
        ch = fgetc(fp_read);
        if(counter % 5 != 0)
        {
            fputc(ch, fp_write);
        }
        else
            i++;
        //printf("%c ", ch);
        counter++;
    }

    fclose(fp_read);
    fclose(fp_write);
    printf("Trucate by %d bytes", i);
    //Here truncate the file by "i" size
    return 0;
}

void removeBytes(char *s, int interval) {
if (s==nil || interval<=0)
return;

//copy *p to *q if it is NOT on interval
//shift p until '\0'
char *q = s;
char *p = s;
int k = interval;
while (*p != '\0') {
k--;
if (k > 0 && p!=q) {
*q++ = *p++;
}
else if (k==0) {
p++;
k = interval;
}
}
*q = '\0';
}

is it bad to convert the byte array to ArrayList and the remove every char for multiple of 5 ?