Modulo:Exponential search

Info

Documentation del modulo

Le documentation de iste modulo non existe ancora. Crea lo!

-- copiate e traducite desde [[:en:Special:Permalink/1138644443]]

-- Iste modulo forni un algorithmo generic de cerca exponential.
require[[strict]]

local checkType = require('libraryUtil').checkType
local floor = math.floor

local function midPoint(lower, upper)
	return floor(lower + (upper - lower) / 2)
end

local function search(testFunc, i, lower, upper)
	if testFunc(i) then
		if i + 1 == upper then
			return i
		end
		lower = i
		if upper then
			i = midPoint(lower, upper)
		else
			i = i * 2
		end
		return search(testFunc, i, lower, upper)
	else
		upper = i
		i = midPoint(lower, upper)
		return search(testFunc, i, lower, upper)
	end
end

return function (testFunc, init)
	checkType('Exponential search', 1, testFunc, 'function')
	checkType('Exponential search', 2, init, 'number', true)
	if init and (init < 1 or init ~= floor(init) or init == math.huge) then
		error(string.format(
			"Valor initial non valide ‘%s’ detegite in le secunde argumento passate a " ..
			"‘Exponential search’ (le valor initial debe esser un numero integre positive)",
			tostring(init)
		), 2)
	end
	init = init or 2
	if not testFunc(1) then
		return nil
	end
	return search(testFunc, init, 1, nil)
end