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1 // Part 1 about the 3n+1 conjecture |
1 // Part 1 about the 3n+1 conjecture |
2 //================================== |
2 //================================== |
3 |
3 |
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4 // generate jar with |
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5 // > scala -d collatz.jar collatz.scala |
4 |
6 |
5 //object CW6a { // for purposes of generating a jar |
7 object CW6a { |
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8 |
6 |
9 |
7 def collatz(n: Long): Long = |
10 def collatz(n: Long): Long = |
8 if (n == 1) 0 else |
11 if (n == 1) 0 else |
9 if (n % 2 == 0) 1 + collatz(n / 2) else |
12 if (n % 2 == 0) 1 + collatz(n / 2) else |
10 1 + collatz(3 * n + 1) |
13 1 + collatz(3 * n + 1) |
13 def collatz_max(bnd: Long): (Long, Long) = { |
16 def collatz_max(bnd: Long): (Long, Long) = { |
14 val all = for (i <- (1L to bnd)) yield (collatz(i), i) |
17 val all = for (i <- (1L to bnd)) yield (collatz(i), i) |
15 all.maxBy(_._1) |
18 all.maxBy(_._1) |
16 } |
19 } |
17 |
20 |
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21 |
18 /* some test cases |
22 /* some test cases |
19 val bnds = List(10, 100, 1000, 10000, 100000, 1000000) |
23 val bnds = List(10, 100, 1000, 10000, 100000, 1000000) |
20 |
24 |
21 for (bnd <- bnds) { |
25 for (bnd <- bnds) { |
22 val (steps, max) = collatz_max(bnd) |
26 val (steps, max) = collatz_max(bnd) |
23 println(s"In the range of 1 - ${bnd} the number ${max} needs the maximum steps of ${steps}") |
27 println(s"In the range of 1 - ${bnd} the number ${max} needs the maximum steps of ${steps}") |
24 } |
28 } |
25 |
29 |
26 */ |
30 */ |
27 |
31 |
28 //} |
32 |
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33 } |
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34 |
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35 |
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36 |