return (function()
local builders = {}
local function register(name, f)
builders[name] = f
end
register('llpeg', function() return require [[Module:User:Cscott/llpeg]] end)
register('pqueue', function(myrequire)
--[[ Priority Queue implemented in lua, based on a binary heap.
Copyright (C) 2017 Lucas de Morais Siqueira <lucas.morais.siqueira@gmail.com>
License: zlib
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgement in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
]]--
-- modified by xxopxe@gmail.com
local floor = math.floor
local PriorityQueue = {}
PriorityQueue.__index = PriorityQueue
setmetatable(
PriorityQueue,
{
__call = function ()
local new = {}
setmetatable(new, PriorityQueue)
new:initialize()
return new
end
}
)
function PriorityQueue:initialize()
--[[ Initialization.
Example:
PriorityQueue = require "priority_queue"
pq = PriorityQueue()
]]--
self.heap_val = {}
self.heap_pri = {}
self.current_size = 0
end
function PriorityQueue:empty()
return self.current_size == 0
end
function PriorityQueue:size()
return self.current_size
end
function PriorityQueue:swim()
-- Swim up on the tree and fix the order heap property.
local heap_val = self.heap_val
local heap_pri = self.heap_pri
local floor = floor
local i = self.current_size
while floor(i / 2) > 0 do
local half = floor(i / 2)
if heap_pri[i] < heap_pri[half] then
heap_val[i], heap_val[half] = heap_val[half], heap_val[i]
heap_pri[i], heap_pri[half] = heap_pri[half], heap_pri[i]
end
i = half
end
end
function PriorityQueue:put(v, p)
--[[ Put an item on the queue.
Args:
v: the item to be stored
p(number): the priority of the item
]]--
--
self.current_size = self.current_size + 1
self.heap_val[self.current_size] = v
self.heap_pri[self.current_size] = p
self:swim()
end
function PriorityQueue:sink()
-- Sink down on the tree and fix the order heap property.
local size = self.current_size
local heap_val = self.heap_val
local heap_pri = self.heap_pri
local i = 1
while (i * 2) <= size do
local mc = self:min_child(i)
if heap_pri[i] > heap_pri[mc] then
heap_val[i], heap_val[mc] = heap_val[mc], heap_val[i]
heap_pri[i], heap_pri[mc] = heap_pri[mc], heap_pri[i]
end
i = mc
end
end
function PriorityQueue:min_child(i)
if (i * 2) + 1 > self.current_size then
return i * 2
else
if self.heap_pri[i * 2] < self.heap_pri[i * 2 + 1] then
return i * 2
else
return i * 2 + 1
end
end
end
function PriorityQueue:pop()
-- Remove and return the top priority item
local heap_val = self.heap_val
local heap_pri = self.heap_pri
local retval, retprio = heap_val[1], heap_pri[1]
heap_val[1], heap_pri[1] = heap_val[self.current_size], heap_pri[self.current_size]
heap_val[self.current_size], heap_pri[self.current_size] = nil, nil
self.current_size = self.current_size - 1
self:sink()
return retval, retprio
end
function PriorityQueue:peek()
-- return the top priority item
return self.heap_val[1], self.heap_pri[1]
end
return PriorityQueue
end)
register('day17', function(myrequire)
--[[ DAY 16 ]]--
local l = myrequire('llpeg')
local PriorityQueue = myrequire('pqueue')
local TRACK_PATH = false
--[[ PARSING ]]--
local Block = {}
Block.__index = Block
function Block:new(args)
return setmetatable(args, self)
end
function Block:__tostring()
return tostring(self.loss)
end
local nl = l.P"\n"
local function make_block(s)
return Block:new{loss=tonumber(s)}
end
local patt = l.P{
"Graph",
Graph = l.Ct( l.V"Row" * (nl^1 * l.V"Row")^0 * nl^0) * -1,
Row = l.Ct( l.V"Block"^1 ),
Block = l.R"09" / make_block,
}
local Graph = {}
Graph.__index = Graph
local function parse(source)
--print(inspect(source))
local ast, errlabel, pos = patt:match(source)
if not ast then
error(string.format("Error at pos %s label '%s'", pos, errlabel))
end
--print('Parsed with success!')
--print(inspect(ast))
return Graph:new(ast)
end
--[[ Part 1 ]]--
function Graph:new(data)
return setmetatable({ data=data }, self)
end
function Graph:at(row,col,default)
return (self.data[row] or {})[col] or default
end
function Graph:rowN()
return #(self.data)
end
function Graph:colN()
return #(self.data[1])
end
local dirmap = {
n= '^',
s= 'v',
e= '>',
w= '<',
}
function Graph:print()
local sum = 0
for r,row in ipairs(self.data) do
for c,val in ipairs(row) do
if val == nil then
val = " "
elseif val.mark then
sum = sum + val.loss
val = "#"
end
io.write(tostring(val))
end
io.write("\n")
end
print(sum)
end
function Graph:link()
for r=1,self:rowN() do
for c=1,self:colN() do
local sp = self:at(r,c)
sp.r, sp.c = r,c
if r > 1 then sp.n = self:at(r-1,c) end
if c > 1 then sp.w = self:at(r,c-1) end
if r < self:rowN() then sp.s = self:at(r+1,c) end
if c < self:colN() then sp.e = self:at(r,c+1) end
end
end
end
function Graph:search(entry, exit, min, max)
local Q = PriorityQueue()
entry = self:at(entry.r, entry.c)
exit = self:at(exit.r, exit.c)
local state = {
block = entry,
dir = nil,
loss = 0, -- entry.loss, "we never entered the entry block"
path = nil,
}
local freelist = {}
local dirs = { "n", "s", "e", "w" }
local reverse = { n='s', s='n', e='w', w='e' }
-- since we can't continue in same direction *or* reverse direction,
-- then we can share "visited" set keys for n/s and e/w
local keymap = { n="visit_n", s="visit_n", e="visit_e", w="visit_e", ["nil"]="visit_nil" }
Q:put(state, state.loss)
local qmax = 0
while not Q:empty() do
state = Q:pop()
if Q:size() > qmax then qmax = Q:size() end
if state.block == exit then
local p = state.path
while p ~= nil do
p[1].mark = true
p = p[2]
end
--self:print()
return state.loss
end
local visit_key = keymap[state.dir or "nil"]
if not state.block[visit_key] then
--print(string.format("Visiting col %d row %d from %s (step %d) with loss %d", state.block.c, state.block.r, state.dir, state.amt, state.loss))
state.block[visit_key] = true
for _,d in ipairs(dirs) do
if d ~= state.dir and d ~= reverse[state.dir] then
local neigh = state.block
local nloss = state.loss
local npath = state.path
for i=1,max do
neigh = neigh[d]
if neigh == nil then break end
nloss = nloss + neigh.loss
if TRACK_PATH then
npath = { neigh, npath }
end
if i >= min then
local nstate
if #freelist > 0 then
nstate = table.remove(freelist)
else
nstate = {}
end
nstate.block = neigh
nstate.dir = d
nstate.loss = nloss
nstate.path = npath
Q:put(nstate, nstate.loss)
end
end
end
end
end
table.insert(freelist, state)
end
return nil
end
local function part1(source)
local graph = parse(source)
graph:link()
return graph:search({r=1,c=1},{r=graph:rowN(),c=graph:colN()}, 1, 3)
end
local function part2(source)
local graph = parse(source)
graph:link()
return graph:search({r=1,c=1},{r=graph:rowN(),c=graph:colN()}, 4, 10)
end
--[[ CLI ] ]--
local source = io.input("day17.input"):read("*a")
print('Loss:', part1(source))
print('Ultra Loss:', part2(source))
--[ [ END CLI ]]--
return {
part1 = function(frame)
local s = mw.title.new(frame.args[1]):getContent()
return part1(s)
end,
part2 = function(frame)
local s = mw.title.new(frame.args[1]):getContent()
return part2(s, tonumber(frame.args[2]))
end,
}
end)
local modules = {}
modules['table'] = require('table')
modules['string'] = require('string')
modules['strict'] = {}
local function myrequire(name)
if modules[name] == nil then
modules[name] = true
modules[name] = (builders[name])(myrequire)
end
return modules[name]
end
return myrequire('day17')
end)()
