day 13: cleaned up a bit

.gitignore

@@ -1,2 +1,3 @@
 */*/input
+*/*/output
 .*.swp

12023/13/13.lua

@@ -0,0 +1,181 @@
+io.input("input")
+
+sum1 = 0
+sum2 = 0
+
+function hex(n) return string.format("%04x",n) end
+
+function reset()
+    len = 0
+    r = 0
+    vindexes = {}
+    hindexes = {}
+    rows = {}
+    cols = {}
+end
+
+function one_difference(a,b) --numeric
+    local diff = a~b
+    -- is power of 2?
+    local log = math.log(diff,2)
+    return (diff>0 and log==math.floor(log)) and diff or nil
+end
+
+function list_of_one_diff(t)
+    local diffs = {}
+    for i=1,#t-1 do
+        for j=i+1,#t do
+            local diff = one_difference(t[i],t[j])
+            if diff then
+                table.insert(diffs,table.pack(i,j,diff))
+            end
+        end
+    end
+    return diffs
+end
+
+function new_reflection(nums,N,ignore)
+    local vdiff = list_of_one_diff(nums)
+    for _, d in ipairs(vdiff) do
+        local i,j,diff = table.unpack(d)
+        local newnums = {}
+        table.move(nums,1,#nums,1,newnums)
+        -- make them equal
+        local newvalue = newnums[j]
+        newnums[i] = newvalue
+
+        --print(i,j,hex(diff),hex(nums[i]),hex(nums[j]),hex(newvalue))
+
+        -- calculate new indexes
+        local indexes = {}
+        for j=1,N do
+            local num = newnums[j]
+            if not indexes[num] then indexes[num]={} end
+            table.insert(indexes[num], j)
+        end
+
+        print("attempt reflection")
+        local r = reflection(indexes, newnums, N,ignore)
+        if r then return r end
+    end
+    return nil
+end
+
+function two_consecutives(t)
+    if #t==1 then return nil
+    else
+        local consecutives = {}
+        for i=1,#t-1 do
+            if t[i]+1==t[i+1] then 
+                table.insert(consecutives, table.pack(t[i], t[i+1]))
+            end
+        end
+        if #consecutives>0 then return consecutives end
+    end
+    return nil
+end
+
+function reflection(indexes, nums, N, ignore)
+    print(N)
+    local consecutives = {}
+    for num, ix in pairs(indexes) do
+        print(hex(num), table.concat(ix,","))
+        local cs = two_consecutives(ix)
+        if cs then
+            for _, c in ipairs(cs) do
+                table.insert(consecutives, c)
+            end
+        end
+    end
+    if #consecutives>0 then
+        print("list of consecutives")
+        for _, c in ipairs(consecutives) do
+            local a,b = table.unpack(c)
+            if a==ignore then goto continue end
+            local x,y = a,b
+            print(a,b)
+            local reflected = true
+            while reflected and x>=1 and y<=N do
+                print("testing",x,y,hex(nums[x]),hex(nums[y]))
+                if nums[x]~=nums[y] then 
+                    reflected = false
+                end
+                x,y = x-1, y+1
+            end
+            print(reflected, a)
+            if reflected then return a end
+            ::continue::
+        end
+    end
+    return nil
+end
+
+function end_of_group()
+    for j=1,len do
+        local vnum = cols[j]
+        if not vindexes[vnum] then vindexes[vnum]={} end
+        table.insert(vindexes[vnum], j)
+    end
+
+    print("vindexes")
+    local vr = reflection(vindexes, cols, len)
+    if vr then
+        print("VR",vr)
+        sum1 = sum1 + vr
+    end
+
+    print("hindexes")
+    local hr = reflection(hindexes, rows, r)
+    if hr then
+        print("HR",hr)
+        sum1 = sum1 + 100*hr
+    end
+
+    -- part 2
+    print("\nPART 2")
+    print("vdifferences")
+    local nvr = new_reflection(cols, len, vr)
+    if nvr then
+        print("NVR",nvr)
+        sum2 = sum2 + nvr
+    end
+
+    print("hdifferences")
+    local nhr = new_reflection(rows, r, hr)
+    if nhr then
+        print("NHR",nhr)
+        sum2 = sum2 + 100*nhr
+    end
+
+    -- reset
+    reset()
+    print()
+end
+
+reset()
+for line in io.lines() do
+    if line:find("[%#%.]") then
+        if r==0 then
+            len = #line
+            for i=1,len do cols[i]=0 end
+        end
+        print(line)
+        r = r+1
+        local hnum = 0
+        for i=1,len do
+            local char = line:sub(i,i)
+            local bit = char=="#" and 1 or 0
+            hnum = (hnum<<1) | bit
+            cols[i] = (cols[i]<<1) | bit
+        end
+        table.insert(rows, hnum)
+        if not hindexes[hnum] then hindexes[hnum]={} end
+        table.insert(hindexes[hnum],r)
+    else
+        end_of_group()
+    end
+end
+end_of_group()
+
+print("part 1", sum1)
+print("part 2", sum2)

12023/13/test

@@ -0,0 +1,15 @@
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#

12023/13/test1

@@ -0,0 +1,13 @@
+##.###..#.###.###
+.###.##......#.##
+..#..##..##.##.##
+..#..##..##.##.##
+.###.##......#.##
+##.###..#.###.###
+..#.#.#..#..###..
+.#.#.#.#.#.#####.
+.#.#.#.#.#.#####.
+..#.#.#..#..###..
+######..#.###.###
+.###.##......#.##
+..#..##..##.##.##