How many strings of n bits are there which differ by exactly m bits?
0
$begingroup$
For example:
If n = 8 and m = 0: ans = 1
If n = 8 and m = 1: ans = 8
If n = 8 and m = 2: ans = ?
If n =256 and m = 3: ans = ?
linear-algebra combinatorics bit-strings
asked Jan 7 at 19:28
d eid ei
31
$endgroup$
add a comment |
0
$begingroup$
For example:
If n = 8 and m = 0: ans = 1
If n = 8 and m = 1: ans = 8
If n = 8 and m = 2: ans = ?
If n =256 and m = 3: ans = ?
linear-algebra combinatorics bit-strings
asked Jan 7 at 19:28
d eid ei
31
$endgroup$
$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30
add a comment |
0
0
0
$begingroup$
For example:
If n = 8 and m = 0: ans = 1
If n = 8 and m = 1: ans = 8
If n = 8 and m = 2: ans = ?
If n =256 and m = 3: ans = ?
linear-algebra combinatorics bit-strings
asked Jan 7 at 19:28
d eid ei
31
$endgroup$
For example:
If n = 8 and m = 0: ans = 1
If n = 8 and m = 1: ans = 8
If n = 8 and m = 2: ans = ?
If n =256 and m = 3: ans = ?
linear-algebra combinatorics bit-strings
linear-algebra combinatorics bit-strings
asked Jan 7 at 19:28
d eid ei
31
asked Jan 7 at 19:28
d eid ei
31
asked Jan 7 at 19:28
d eid ei
31
asked Jan 7 at 19:28
d eid ei
31
asked Jan 7 at 19:28
d eid ei
31
31
$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30
add a comment |
$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30
$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30
$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30
add a comment |
1 Answer
1
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oldest
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1
$begingroup$
Just choose the $m$ bits out of $n$ to be different, so $n choose m$
edited Jan 7 at 19:31
John Doe
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
$endgroup$
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
add a comment |
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1 Answer
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1 Answer
1
active
oldest
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active
oldest
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active
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votes
1
$begingroup$
Just choose the $m$ bits out of $n$ to be different, so $n choose m$
edited Jan 7 at 19:31
John Doe
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
$endgroup$
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
add a comment |
1
$begingroup$
Just choose the $m$ bits out of $n$ to be different, so $n choose m$
edited Jan 7 at 19:31
John Doe
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
$endgroup$
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
add a comment |
1
1
1
$begingroup$
Just choose the $m$ bits out of $n$ to be different, so $n choose m$
edited Jan 7 at 19:31
John Doe
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
$endgroup$
Just choose the $m$ bits out of $n$ to be different, so $n choose m$
edited Jan 7 at 19:31
John Doe
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
edited Jan 7 at 19:31
John Doe
12.1k11339
edited Jan 7 at 19:31
John Doe
12.1k11339
edited Jan 7 at 19:31
John Doe
12.1k11339
12.1k11339
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
answered Jan 7 at 19:30
Ross MillikanRoss Millikan
301k24200375
301k24200375
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
add a comment |
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
$begingroup$
You're right of course. Thanks!
$endgroup$
– d ei
Jan 9 at 20:50
add a comment |
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$begingroup$
Isn't this just $nchoose m$? Perhaps I am misinterpreting the question..
$endgroup$
– John Doe
Jan 7 at 19:30