50 lines
1.2 KiB
Lua
50 lines
1.2 KiB
Lua
local function add(self, item)
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table.insert(self.items, item)
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local i, p = #self.items
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local p = math.floor(i / 2)
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while i > 1 and self.smaller(self.items[i], self.items[p]) do
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self.items[p], self.items[i] = self.items[i], self.items[p]
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i, p = p, math.floor(p / 2)
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end
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end
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local function pop(self)
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local item = self.items[1]
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self.items[1] = self.items[#self.items]
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table.remove(self.items)
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local i = 1
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while i * 2 <= #self.items do
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if i * 2 + 1 <= #self.items then
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if self.smaller(self.items[i*2], self.items[i])
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or self.smaller(self.items[i*2+1], self.items[i]) then
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if self.smaller(self.items[i*2], self.items[i*2+1]) then
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self.items[i], self.items[i*2], i
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= self.items[i * 2], self.items[i], i * 2
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else
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self.items[i], self.items[i*2+1], i
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= self.items[i*2+1], self.items[i], i * 2 + 1
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end
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else
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break
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end
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else
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if self.smaller(self.items[i*2], self.items[i]) then
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self.items[i], self.items[i * 2]
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= self.items[i * 2], self.items[i]
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end
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i = i * 2
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end
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end
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return item
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end
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function pqueue(smaller)
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return {
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items = {},
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smaller = smaller
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or function(a, b) return a < b end,
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add = add,
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pop = pop,
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}
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end
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