18 lines
515 B
Text
18 lines
515 B
Text
# Returns a copy of an array with the element at a specific position
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# removed from it.
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arrayExcept = (arr, idx) ->
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res = arr[0..]
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res.splice idx, 1
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res
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# The actual function which returns the permutations of an array-like
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# object (or a proper array).
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permute = (arr) ->
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arr = Array::slice.call arr, 0
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return [[]] if arr.length == 0
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permutations = (for value,idx in arr
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[value].concat perm for perm in permute arrayExcept arr, idx)
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# Flatten the array before returning it.
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[].concat permutations...
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