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127
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// Part 1 about the 3n+1 conjecture
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//==================================
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167
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281
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// generate jar with
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// > scala -d collatz.jar collatz.scala
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126
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281
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object CW6a {
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126
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127
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def collatz(n: Long): Long =
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199
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if (n == 1) 0 else
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127
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if (n % 2 == 0) 1 + collatz(n / 2) else
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1 + collatz(3 * n + 1)
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126
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127
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def collatz_max(bnd: Long): (Long, Long) = {
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199
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val all = for (i <- (1L to bnd)) yield (collatz(i), i)
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all.maxBy(_._1)
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126
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}
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281
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199
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/* some test cases
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val bnds = List(10, 100, 1000, 10000, 100000, 1000000)
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126
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199
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for (bnd <- bnds) {
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val (steps, max) = collatz_max(bnd)
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println(s"In the range of 1 - ${bnd} the number ${max} needs the maximum steps of ${steps}")
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127
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}
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126
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199
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*/
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171
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281
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}
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