9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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changeset
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1 |
import scala.annotation.tailrec
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
2 |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
3 |
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11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
4 |
def collatz(n: Long): List[Long] =
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9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
5 |
if (n == 1) List(1) else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
6 |
if (n % 2 == 0) (n::collatz(n / 2)) else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
7 |
(n::collatz(3 * n + 1))
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
8 |
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11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
9 |
def collatz1(n: Long): Int =
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9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
10 |
if (n == 1) 1 else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
11 |
if (n % 2 == 0) (1 + collatz1(n / 2)) else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
12 |
(1 + collatz1(3 * n + 1))
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
13 |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
14 |
@tailrec
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10
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
15 |
def collatz2(n: Long, acc: Int): Int =
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9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
16 |
if (n == 1) acc else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
17 |
if (n % 2 == 0) collatz2(n / 2, acc + 1) else
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
18 |
collatz2(3 * n + 1, acc + 1)
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
19 |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
20 |
collatz(1)
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
21 |
collatz(2)
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
22 |
collatz(3)
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
23 |
collatz(4)
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
24 |
collatz(5)
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11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
25 |
collatz(6).length
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9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
26 |
collatz(7)
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
27 |
collatz(8)
|
11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
28 |
collatz(9).length
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9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
29 |
collatz(100000)
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11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
30 |
println((for (i <- 1 to 10000000) yield collatz(i).length).max)
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Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
31 |
println((for (i <- 1 to 10000000) yield collatz1(i)).max)
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
32 |
println((for (i <- 1 to 10000000) yield collatz2(i, 1)).max)
|
9
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
33 |
println((for (i <- (1 to 10000000).par) yield collatz2(i, 1)).max)
|
11
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
34 |
|