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1 // Part 1 about the 3n+1 conjecture |
1 // Part 1 about the 3n+1 conjecture |
2 //================================== |
2 //================================== |
3 package CW6a |
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4 |
3 |
5 |
4 |
6 object CW6a { |
5 //object CW6a { // for purposes of generating a jar |
7 |
6 |
8 def collatz(n: Long): Long = |
7 def collatz(n: Long): Long = |
9 if (n == 1) 1 else |
8 if (n == 1) 0 else |
10 if (n % 2 == 0) 1 + collatz(n / 2) else |
9 if (n % 2 == 0) 1 + collatz(n / 2) else |
11 1 + collatz(3 * n + 1) |
10 1 + collatz(3 * n + 1) |
12 |
11 |
13 |
12 |
14 def collatz_max(bnd: Long): (Long, Long) = { |
13 def collatz_max(bnd: Long): (Long, Long) = { |
15 val all = for (i <- (1 to bnd.toInt).toList) yield collatz(i) |
14 val all = for (i <- (1L to bnd)) yield (collatz(i), i) |
16 val max = all.max |
15 all.maxBy(_._1) |
17 (max, all.indexOf(max) + 1) |
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18 } |
16 } |
19 |
17 |
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18 /* some test cases |
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19 val bnds = List(10, 100, 1000, 10000, 100000, 1000000) |
20 |
20 |
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21 for (bnd <- bnds) { |
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22 val (steps, max) = collatz_max(bnd) |
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23 println(s"In the range of 1 - ${bnd} the number ${max} needs the maximum steps of ${steps}") |
21 } |
24 } |
22 |
25 |
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26 */ |
23 |
27 |
24 |
28 //} |
25 (1 to 10).map(collatz(_)) |
|