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Move lua solution to lua branch

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William Brawner 2023-12-11 22:12:52 -07:00
parent 7bb010e126
commit bd6f4cc5c5
Signed by: wbrawner
GPG key ID: 8FF12381C6C90D35
1 changed files with 0 additions and 92 deletions
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src/Day08.lua
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@ -1,92 +0,0 @@
---@diagnostic disable: lowercase-global
require "util"
function parse_node(line)
local matches = {}
for match in line:gmatch("%w+") do
matches[#matches + 1] = match
end
return matches[1], { L = matches[2], R = matches[3] }
end
function values(src)
local dest = {}
for _,v in pairs(src) do
dest[#dest + 1] = v
end
return dest
end
function part1(input)
local steps = input[1]
local nodes = {}
for i = 3, #input do
local node, children = parse_node(input[i])
nodes[node] = children
end
local current_node = "AAA"
local step_index = 1
local step_count = 0
while current_node ~= "ZZZ" do
local nextStep = steps:sub(step_index, step_index)
current_node = nodes[current_node][nextStep]
step_count = step_count + 1
step_index = step_index + 1
if step_index > #steps then
step_index = 1
end
end
return step_count
end
function find_lcm(first, second)
local max = math.max(first, second)
local fcm = first * second
local cm = max
io.write(string.format("finding lcm of %s and %s... ", first, second))
while cm <= fcm do
if (cm % first == 0 and cm % second == 0) then
print(cm)
return cm
end
cm = cm + max
end
end
function part2(input)
local steps = input[1]
local nodes = {}
local current_nodes = {}
for i = 3, #input do
local node, children = parse_node(input[i])
nodes[node] = children
if string.sub(node, #node, #node) == "A" then
current_nodes[node] = 0
end
end
for node, _ in pairs(current_nodes) do
local step_index = 1
local current_node = node
while current_node:sub(#current_node, #current_node) ~= "Z" do
local nextStep = steps:sub(step_index, step_index)
current_node = nodes[current_node][nextStep]
current_nodes[node] = current_nodes[node] + 1
step_index = step_index + 1
if step_index > #steps then
step_index = 1
end
end
end
local node_steps = values(current_nodes)
local lcm = find_lcm(node_steps[1], node_steps[2])
for i = 3, #node_steps do
lcm=find_lcm(lcm, node_steps[i])
end
return lcm
end
local test_input = readInput("day08_test.txt")
local input = readInput("day08.txt")
print(part1(input))
assert_equals(part2(test_input), 6)
print(part2(input))