75 lines
1.6 KiB
Lua
75 lines
1.6 KiB
Lua
io.input("test")
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io.input("input")
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stacks = {}
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stacks2 = {}
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instructions = {}
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count = 0
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function printStacks()
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for i,stack in ipairs(stacks) do
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local s = ""
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for _,j in ipairs(stack) do
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s = s .. j
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end
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print(i, s)
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end
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end
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-- parsing
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for line in io.lines() do
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if string.find(line, "%[%a%]") then
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local nstacks = #line//4 + 1 -- 1 5 9
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for i = 1,nstacks do
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if count == 0 then
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stacks[i] = {}
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stacks2[i] = {}
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end
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local index = 1 + (i-1)*4 -- 1, 5, 9
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local s = string.sub(line, index, index+3)
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local t = string.match(s, "%[(%a)%]")
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table.insert( stacks[i], 1, t )
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table.insert( stacks2[i], 1, t )
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end
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elseif string.find(line, "^move") then
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local pattern = "^move (%d+) from (%d+) to (%d+)$"
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local tt = table.pack(string.match(line, pattern))
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local t = {}
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for j, v in ipairs(tt) do t[j] = tonumber(v) end
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table.insert(instructions, t)
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end
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count = count + 1
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end
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-- moves
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for i, t in ipairs(instructions) do
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q, src, dst = table.unpack(t)
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-- part 1
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for n = 1,q do
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local crate = table.remove( stacks[src] )
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table.insert( stacks[dst], crate )
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end
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-- part 2
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local crates = {}
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for n = 1,q do
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crates[q-n+1] = table.remove( stacks2[src] )
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end
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for n = 1,q do
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table.insert( stacks2[dst], crates[n] )
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end
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end
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-- result
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local result = ""
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for _, stack in ipairs(stacks) do
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result = result .. stack[#stack]
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end
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print("part 1", result)
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result = ""
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for _, stack in ipairs(stacks2) do
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result = result .. stack[#stack]
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end
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print("part 2", result)
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