attempting day 12, part 2 XD

12023/12/12.lua

@@ -0,0 +1,94 @@
+io.input("input")
+
+function is_valid_arrangement(s_damaged, s_proposed)
+    for i=1,#s_damaged do
+        local d, p = s_damaged:sub(i,i), s_proposed:sub(i,i)
+        if d=="#" and p=="." or d=="." and p=="#"then
+            return false
+        end
+    end
+    return true
+end
+
+function gen_proposed(len, g, init)
+    local t = {}
+    local ins
+    for i=1,len do
+        if i>=init and i<init+g then
+            ins = "#"
+        else ins = "." end
+        table.insert(t,ins)
+    end
+    return table.concat(t)
+end
+
+function sum(t)
+    local count = 0
+    for i,v in ipairs(t) do count=count+v end
+    return count
+end
+
+function count_arrangements(s_damaged, groups)
+    local groups_copy = {}
+    table.move(groups, 1, #groups, 1, groups_copy)
+    local g = table.remove(groups_copy,1)
+    local count = 0
+    local len = #s_damaged
+    if #groups_copy==0 then --last element
+        for i=1,len-g+1 do
+            local prop = gen_proposed(len, g, i)
+            local is_valid = is_valid_arrangement(s_damaged, prop)
+            if is_valid then count = count + 1 end
+        end
+    else -- uy uy uy
+        local n_remaining = #groups_copy
+        local sum_remaining = sum(groups_copy)
+        local buffer = n_remaining + sum_remaining
+        local active = len - buffer + 1
+        for i=1,len-buffer do
+            local prop_len = g+i
+            local subd = s_damaged:sub(1,prop_len)
+            local prop = gen_proposed(prop_len, g, i)
+            local is_valid = is_valid_arrangement(subd, prop) 
+            --print("group"..g,subd, prop, is_valid, s_damaged, prop_len, len)
+            if is_valid then
+                local d_remaining = s_damaged:sub(prop_len+1)
+                --print(g,d_remaining)
+                count = count + count_arrangements(d_remaining, groups_copy)
+            end
+        end
+    end
+    return count
+end
+
+n = 1
+sum1 = 0
+sum2 = 0
+for line in io.lines() do
+    --print(line)
+    print("line",n)
+    n = n + 1
+    map, records_list = line:match("([%#%.%?]+) ([%d%,]+)$")
+    records = {}
+    for r in records_list:gmatch("(%d+)") do
+        table.insert(records, tonumber(r))
+    end
+    local count = count_arrangements(map, records)
+    sum1 = sum1 + count
+
+    -- part 2
+    local newmap = map
+    local newrecords = {}
+    table.move(records,1,#records,1,newrecords)
+    for i=1,4 do
+        newmap = newmap .."?"..map
+        table.move(records,1,#records,1 + #records*i,newrecords)
+    end
+    print(newmap)
+    local count2 = count_arrangements(newmap, newrecords)
+    sum2 = sum2 + count2
+    print(count2)
+end
+
+print("part 1", sum1)
+print("part 2", sum2)

12023/12/test

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+???.### 1,1,3
+.??..??...?##. 1,1,3
+?#?#?#?#?#?#?#? 1,3,1,6
+????.#...#... 4,1,1
+????.######..#####. 1,6,5
+?###???????? 3,2,1