// Core Part 1 about the 3n+1 conjecture+
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//============================================+
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+
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object C1 {+
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+
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// ADD YOUR CODE BELOW+
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//======================+
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+
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// test1 7 Nov+
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// test2+
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// test3+
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// test4+
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+
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+
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//(1) +
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def collatz(n: Long) : Long = +
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  if (n == 1) 0 else+
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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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+
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+
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//(2) +
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//def collatz_max(bnd: Long) : (Long, Long) = {+
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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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//}+
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+
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def collatz_max(bnd: Long): (Long, Long) = {+
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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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}+
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+
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+
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+
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//(3)+
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+
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def is_pow_of_two(n: Long) : Boolean = (n & (n - 1)) == 0+
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+
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def is_hard(n: Long) : Boolean = is_pow_of_two(3 * n + 1)+
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+
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def last_odd(n: Long) : Long = if (is_hard(n)) n else+
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    if (n % 2 == 0) last_odd(n / 2) else +
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      last_odd(3 * n + 1)+
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+
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}+
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+
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+
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+
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// This template code is subject to copyright +
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// by King's College London, 2022. Do not +
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// make the template code public in any shape +
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// or form, and do not exchange it with other +
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// students under any circumstance.+
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