How to find for the first index of contiguous set of 0 bits in java?

Asked May 26 '15 at 19:56

Active May 26 '15 at 20:14

Viewed 85 times

I need to write a method thatshould search for the first contiguous set of free blocks that is at least numBlocks in size. It should return the index of the first block in the sequence. If no such sequence exists, return -1.

For example, if the file originally contained the bytes (shown in hex) “3f fc 40 1f” and numBlocks is 4, the method should return 18 (the bit representation of this file is 00111111111111000100000000011111, so the first sequence of 0s of length at least 4 starts at bit 18).

The function start like this:

    public long findSpace(RandomAccessFile file, int num) throws IOException {

    long size = file.length();
    long numBits = size*8;



}

asked May 26 '15 at 19:56

oy1

Is the brute force approach insufficient for your case? – Kon May 26 '15 at 20:01
1

[What have you tried?](http://mattgemmell.com/what-have-you-tried/) – RealSkeptic May 26 '15 at 20:01
You can read them in one by one and count the 0s encountered, resetting the counter whenever you hit a 1. – biziclop May 26 '15 at 20:02
1

Sorry but this is not the same. It migh lead to his solution, but it is not a duplicate. – maraca May 26 '15 at 20:21
1

@JarrodRoberson Im curious about the duplicate. – Jean-François Savard May 26 '15 at 20:22
1

Actually what he's trying to do is much more complicated to do in a performant way. I advise you to ask the question again with more details and more code, even if it is not working it is better than nothing. – maraca May 26 '15 at 20:37

How to find for the first index of contiguous set of 0 bits in java?

0 Answers0