25 lines
740 B
CoffeeScript
25 lines
740 B
CoffeeScript
# Uses a binary search algorithm to locate a value in the specified array.
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binary_search: (items, value) =>
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start: 0
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stop: items.length - 1
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pivot: Math.floor((start + stop) / 2)
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while items[pivot] isnt value and start < stop
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# Adjust the search area.
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stop: pivot - 1 if value < items[pivot]
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start: pivot + 1 if value > items[pivot]
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# Recalculate the pivot.
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pivot: Math.floor((stop + start) / 2)
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# Make sure we've found the correct value.
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if items[pivot] is value then pivot else -1
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# Test the function.
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print(2 is binary_search([10, 20, 30, 40, 50], 30))
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print(4 is binary_search([-97, 35, 67, 88, 1200], 1200))
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print(0 is binary_search([0, 45, 70], 0))
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print(-1 is binary_search([0, 45, 70], 10)) |