Find sum of odd numbers

Question

Write a program to find the sum of all odd numbers between a given range [a,b]. Input consists of a single line containing two integers a and b separated by a space. 0 ≤ a,b ≤ 1,000,000,000,000. Your program should not take more than 10 secs.

Sample Inputs
1 5
4 8
1 8
0 5

Sample Outputs
9
12
16
9

Answer 1

Ruby, 43 characters

p eval"-(%d/2)**2+((%d+1)/2)**2"%gets.split

Example for largest input:

$ time echo "1 10000000000000000" | ruby oddsum.rb
25000000000000000000000000000000

real    0m0.006s
user    0m0.000s
sys     0m0.000s

Answer 2

Funciton

Not a language particularly suitable for golfing, but I gave it my best shot to cram everything together in best code-golf tradition. Near the end I was making rearrangements that gave net savings of a single character until I could find no more ways to improve it :)

This is 398 characters (or 786 bytes in UTF-16). I challenge anyone to find a way to make it smaller :)

 ┌───┐    ┌──────────┐
╔╧╗┌─┴╖┌─╖│╔═╗┌──╖┌─╖│
║ ║│>>╟┤_╟┘║1╟┤>>╟┤♯╟┘
╚═╝╘╤═╝╘═╝ ╚═╝╘═╤╝╘═╝
    └┐ ┌─┐ ╔══╗┌┴───┐
╔══╗┌┴╖│┌┴╖║32║│ ┌─╖│
║21╟┤×╟┘│♯║╚╤═╝└─┤×╟┘
╚══╝╘═╝ ╘╤╝┌┘ ┌─┐╘╤╝
┌──────┬─┘┌┘ ┌┴╖└─┘
│╔═╗  ┌┴╖┌┘  │−╟┐┌───────╖
│║0║ ┌┤ʘ╟┘┌─┐╘╤╝└┤int→str╟
│╚╤╝ │╘═╝┌┴╖└─┘  ╘═══════╝
│┌┴╖╔╧╗┌─┤×╟┐
└┤ʃ╟╢ ║│ ╘═╝│
 ╘╤╝╚═╝└┬───┘
  │┌─╖┌─┴╖╔═╗╓─╖┌───────╖
  └┤_╟┤>>╟╢1║║_╟┤str→int╟
   ╘═╝╘══╝╚═╝╙─╜╘═══════╝

Answer 3

Haskell - 65

f[l,h]=print$sum$filter odd[l..h]
main=getLine>>=f.map read.words

Answer 4

Windows PowerShell, 84 61 55

$a,$b=-split"$input+1"|iex|%{($_-band-2)/2}
$b*$b-$a*$a

O(1) runtime.

Answer 5

Golfscript - 12 chars

~)2/2?\2/2?-

can be done in 11 chars if the order of the inputs is reversed

~)]{2/2?}/-

Answer 6

Bash, 37

seq `cat`|grep [13579]$|paste -sd+|bc

53 → 41: Replaced awk '{s+=$1}END{print s}' with paste -sd+|bc. Thanks goes to Dimitre Radoulov's answer to a StackOverflow question.

41 -> 37: Replaced read i;seq $i with seq `cat`

Answer 7

Wolfram Alpha (12 16 chars)

[Input]to[Input] sum n*(n%2

See example here.