Towers of Hanoi: Difference between revisions
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(→{{header|AppleScript}}: Added alternative example.) |
m (→{{header|AppleScript}}: Modified own example to eliminate tail calls.) |
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----
More illustratively:
''(I've now eliminated the recursive ''|move|()'' handler's tail calls. So it's now only called 2 ^ (n - 1) times as opposed to 2 ^ (n + 1) - 1 with full recursion. The maximum call depth of n is only reached once, whereas with full recursion, the maximum depth was n + 1 and this was reached 2 ^ n times.)''
<lang applescript>on hanoi(n)
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on |move|(n, source, target, aux)
|move|(n - 1, source, aux, target)
set
set sourceTowerRef's contents to reverse of rest of reverse of sourceTowerRef▼
set m to m + 1
set end of my process to ¬
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t2 & tower2, ¬
t3 & tower3}
set aux to it
end tell
end repeat
-- Specific code for n = 1:
set end of item target of my towerRefs to 1
▲ tell item source of my towerRefs to set
set m to m + 1
set end of my process to ¬
{(m as text) & ". move disc 1 from tower " & source & (" to tower " & target & ":"), ¬
t1 & tower1, ¬
t2 & tower2, ¬
t3 & tower3}
end |move|
end script
Line 328 ⟶ 341:
set AppleScript's text item delimiters to ", "
set o's process to {"Starting with " & n & " discs on tower 1:", t1 & o's tower1, t2, t3}
if (n > 0) then tell o to |move|(n, 1, 2, 3)
set end of o's process to "That's it!"
set AppleScript's text item delimiters to linefeed
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