158 lines
3.0 KiB
Lua
158 lines
3.0 KiB
Lua
Stack = {}
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function Stack:new()
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local o = {}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function Stack:push(value)
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table.insert(self, value)
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end
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function Stack:pop()
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return table.remove(self)
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end
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function Stack:top()
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return self[#self]
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end
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function Stack:reverse()
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local newStack = Stack:new()
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while #self > 0 do
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newStack:push(self:pop())
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end
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return newStack
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end
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function string:split(delimiter)
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delimiter = delimiter or " "
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result = {};
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for match in (self..delimiter):gmatch("(.-)"..delimiter) do
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table.insert(result, match);
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end
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return result;
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end
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function deepcopy(orig, copies)
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copies = copies or {}
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local orig_type = type(orig)
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local copy
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if orig_type == 'table' then
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if copies[orig] then
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copy = copies[orig]
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else
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copy = {}
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copies[orig] = copy
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for orig_key, orig_value in next, orig, nil do
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copy[deepcopy(orig_key, copies)] = deepcopy(orig_value, copies)
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end
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setmetatable(copy, deepcopy(getmetatable(orig), copies))
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end
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else -- number, string, boolean, etc
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copy = orig
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end
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return copy
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end
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-- Read input data
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if arg[1] == nil then
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print("Usage: "..arg[0].." <filename>")
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os.exit(1)
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end
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file = io.open(arg[1], "r")
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if file == nil then
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print("File not found: "..arg[1])
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os.exit(1)
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end
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inputLines = file:read("all")
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file:close()
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parts = inputLines:split("\n\n")
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initialState = parts[1]:split("\n")
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moves = parts[2]:split("\n")
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-- Initialize stacks
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stackCount = (#initialState[1] + 1) // 4
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stacks = {}
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for i = 1, stackCount do
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stacks[i] = Stack:new()
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end
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-- Fill stacks
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for i = 1, #initialState-1 do
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for j = 1, stackCount do
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letter = string.sub(initialState[i], 4 * j - 2, 4 * j - 2)
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if letter ~= " " then
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stacks[j]:push(letter)
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end
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end
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end
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for i = 1, #stacks do
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stacks[i] = stacks[i]:reverse()
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end
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stacks2 = deepcopy(stacks)
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print("Initial state:")
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for i = 1, stackCount do
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print("Stack "..i..": "..table.concat(stacks[i], " "))
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end
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print("")
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-- Perform moves
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-- Part 1
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for i = 1, #moves do
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move = moves[i]:split()
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count = tonumber(move[2])
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from = tonumber(move[4])
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to = tonumber(move[6])
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for j = 1, count do
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stacks[to]:push(stacks[from]:pop())
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end
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end
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part1 = ""
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for i = 1, stackCount do
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part1 = part1..stacks[i]:top()
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end
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print("Part 1: "..part1)
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-- print("Final state:")
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-- for i = 1, stackCount do
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-- print("Stack "..i..": "..table.concat(stacks[i], " "))
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-- end
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-- Part 2
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for i = 1, #moves do
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move = moves[i]:split()
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count = tonumber(move[2])
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from = tonumber(move[4])
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to = tonumber(move[6])
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temp = Stack:new()
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for j = 1, count do
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temp:push(stacks2[from]:pop())
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end
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-- print("Move "..i..": "..table.concat(temp, " "))
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for j = 1, count do
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stacks2[to]:push(temp:pop())
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end
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end
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part2 = ""
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for i = 1, stackCount do
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part2 = part2..stacks2[i]:top()
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end
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print("Part 2: "..part2)
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