Question
A Pythagorean triplet is a set of three natural numbers, a \lt b \lt c, for which
a^2 + b^2 = c^2
For example, 3^2 + 4^2 = 9 + 16 = 25 = 5^2.
There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a \times b \times c.
Clojure
#!/usr/bin/env clojuredefn square [n]
(* n n))
(
defn triple? [a b c]
(and
(and (> a 0) (> b 0) (> c 0))
(and (< a b) (< b c))
(= (+ (square a) (square b)) (square c))))
(
defn candidates [limit]
(for [a (range 1 (inc limit))
(range a (inc limit))
b (range b (inc limit))
c (:when (and
= (+ a b c) 1000)
(
(triple? a b c))] list a b c)))
(
println (reduce * (first (candidates 500)))) (
$ time clojure pythagorean-triples.clj
real 0m1.600s
user 0m2.626s
sys 0m0.299s
Go
package main
import "fmt"
func main() {
var a, b, c, lb int
:= 1000
max for a = 1; a < max; a++ {
= max - a
lb for b = a; b < lb; b++ {
= max - (a + b)
c if a*a+b*b == c*c {
.Println(a * b * c)
fmtreturn
}
}
}
}
$ go build -o pythagorean pythagorean.go
$ time ./pythagorean
real 0m0.001s
user 0m0.000s
sys 0m0.001s
Haskell
main :: IO ()
= print $ head [a*b*c | a <- [1..500], b <- [a..500], c <- [b..500],
main +b+c == 1000, a*a + b*b == c*c] a
$ ghc -O2 -o pythagorean pythagorean.hs
$ time ./pythagorean
real 0m0.376s
user 0m0.368s
sys 0m0.008s
JavaScript
for (let a = 1; a < 1000; a++) {
for (let b = a, lb = 1000 - a; b < lb; b++) {
const c = 1000 - (a + b)
if (a * a + b * b === c * c) {
return console.log(a * b * c)
}
} }
$ time node --use-strict pythagorean.js
real 0m0.054s
user 0m0.047s
sys 0m0.008s
Ruby
#!/usr/bin/env ruby
for a in (1..500)
for b in (a..500)
for c in (b..500)
if a**2 + b**2 == c**2 and a+b+c == 1000
puts a*b*c
end
end
end
end
$ time ruby pythagorean-triples.rb
real 0m3.244s
user 0m3.227s
sys 0m0.016s
Rust
fn main() {
for a in 1..1000 {
for b in a..(1000 - a) {
let c = 1000 - (a + b);
if a * a + b * b == c * c {
return println!("{}", a * b * c);
}
}
}
}
$ rustc -C target-cpu=native -C opt-level=3 -o pythagorean pythagorean.rs
$ time ./pythagorean
real 0m0.001s
user 0m0.000s
sys 0m0.001s