removed inputs

.gitignore

@@ -0,0 +1 @@
+*/*/input

12021/README.md

@@ -0,0 +1,51 @@
+# awk aoc 2021
+
+got caught in the thrill of wanting to solve the puzzles fast :)
+
+[advent of code 2021: awk](https://compudanzas.net/advent_of_code_2021.html)
+
+the `NUM.awk` and `NUM_2.awk` files are the original ones written under pressure. the `*_new.awk` files are improved versions written afterwards.
+
+you can see the puzzles and get the input files at [advent of code 2021](https://adventofcode.com/2021/)
+
+# run
+
+to run a program, e.g. `01.awk`:
+
+```
+awk -f 01.awk inputfile
+```
+
+if using gawk, you should be able to use compatibility/traditional mode (except for day 03, and 09)
+
+```
+awk -c -f 01.awk inputfile
+```
+
+# stats
+
+```
+      -------Part 1--------   -------Part 2--------
+Day       Time  Rank  Score       Time  Rank  Score
+ 22   00:19:18  1596      0          -     -      -
+ 21   00:29:17  3064      0          -     -      -
+ 20   12:59:28 11947      0   13:14:02 11669      0 --- same as 18
+ 18      >24h  16659      0      >24h  16484      0 --- solved it afterwards
+ 17   00:41:03  2839      0   00:56:57  2841      0
+ 16   00:34:15   550      0   02:21:09  3657      0
+ 15   16:52:00 24420      0   17:30:02 20656      0 --- thanks alderwick for your help!
+ 14   00:27:53  4878      0   01:07:47  3311      0
+ 13   02:02:33  9507      0   02:19:53  9225      0 --- started late
+ 12   01:57:59  7241      0   02:16:49  6447      0
+ 11   00:46:21  4284      0   00:49:55  4145      0
+ 10   00:19:04  4202      0   00:28:32  3347      0
+  9   00:12:52  2598      0   00:55:08  4504      0
+  8   00:06:26   580      0   01:02:03  2196      0
+  7   00:06:50  2657      0   00:12:29  2665      0
+  6   00:10:35  3339      0   00:36:30  4445      0
+  5   00:08:39   464      0   00:19:44   917      0
+  4   00:42:46  4241      0   00:45:01  3008      0
+  3   00:12:37  4213      0   00:38:29  3758      0
+  2   00:02:08   324      0   00:06:30  1842      0
+  1   00:03:11  1556      0   00:08:18  1774      0
+```

12022/01/01.fnl

@@ -0,0 +1,13 @@
+(io.input "input")
+
+(var calories [0])
+
+(each [line (io.lines)]
+  (if (= line "") (table.insert calories 0) 
+    (let [i (length calories)]
+      (tset calories i (+ (tonumber line) (. calories i))))))
+
+(table.sort calories (λ [a b] (> a b)))
+
+(print "part 1" (. calories 1))
+(print "part 2" (let [c calories] (+ (. c 1) (. c 2) (. c 3))))

12022/01/01.lua

@@ -0,0 +1,47 @@
+io.input("test")
+io.input("input")
+
+calories = {0}
+i = #calories
+for line in io.lines() do
+	if line ~= "" then
+		calories[i] = calories[i] + tonumber(line)
+	else
+		table.insert(calories, 0)
+		i = #calories
+	end
+end
+
+max = 0
+maxa, maxb, maxc = 0, 0, 0
+for i, c in ipairs(calories) do
+	if c>max then
+		max = c
+	end
+	if c>maxa then
+		maxc = maxb
+		maxb = maxa
+		maxa = c
+	elseif c>maxb then
+		maxc = maxb
+		maxb = c
+	elseif c>maxc then
+		maxc = c
+	end
+--	print(c)
+end
+
+part1 = maxa
+part2 = maxa+maxb+maxc
+assert(part1==71506)
+assert(part2==209603)
+print("part 1", part1)
+print("part 2", part2)
+
+-- using table.sort
+table.sort(calories, function(a,b) return (a>b) end)
+part1 = calories[1]
+part2 = calories[1]+calories[2]+calories[3]
+print("part 1", part1)
+print("part 2", part2)
+

12022/01/01_copy.fnl

@@ -0,0 +1,22 @@
+(io.input "input")
+
+(local n 3)
+
+(var max [0 0 0]) ; greatest is position 1, then 2, last 3
+(var calories-sum 0)
+
+(each [line (io.lines)]
+  (let [num (tonumber line)] 
+    (if (not num) 
+      (let [ s calories-sum
+        ; count to how many "max" the new sum is greater than
+        greater-than 
+          (accumulate [sum 0 _ m (ipairs max)] (+ sum (if (> s m) 1 0)))]
+        (set calories-sum 0)
+        (when (> greater-than 0) 
+          (table.insert max (- (+ n 1) greater-than) s) ; insert new max
+          (table.remove max))) ; remove last element
+      (set calories-sum (+ calories-sum num)))))
+
+(print "part 1" (. max 1))
+(print "part 2" (accumulate [sum 0 _ m (ipairs max)] (+ sum m)))

12022/01/test

@@ -0,0 +1,14 @@
+1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000

12022/02/02.fnl

@@ -0,0 +1,28 @@
+(io.input "input")
+
+; rock, paper, scissors
+(local own-scores-1 {:X 1 :Y 2 :Z 3})
+(local game-scores {:X {:A 3 :B 0 :C 6}
+                    :Y {:A 6 :B 3 :C 0}
+                    :Z {:A 0 :B 6 :C 3}})
+
+                     ; lose, draw, win
+(local own-scores-2 {:X 0 :Y 3 :Z 6})
+(local game-moves  {:X {:A 3 :B 1 :C 2}
+                    :Y {:A 1 :B 2 :C 3}
+                    :Z {:A 2 :B 3 :C 1}})
+
+(var score-1 0)
+(var score-2 0)
+
+(each [line (io.lines)]
+  (let [(other you) (string.match line "(%a+) (%a)") 
+    move-score (. own-scores-1 you) 
+    round-score (. (. game-scores you) other)
+    own-score-2 (. own-scores-2 you)
+    move-score-2 (. (. game-moves you) other)]
+    (set score-1 (+ score-1 move-score round-score))
+    (set score-2 (+ score-2 own-score-2 move-score-2))))
+
+(print "part 1" score-1)
+(print "part 2" score-2)

12022/02/02.lua

@@ -0,0 +1,25 @@
+io.input("test")
+io.input("input")
+
+-- Rock, paper, scisors
+own_scores = { X=1, Y=2, Z=3 } 
+game_scores = { X = { A=3, B=0, C=6},
+                Y = { A=6, B=3, C=0},
+                Z = { A=0, B=6, C=3}}
+
+		-- lose, draw, win
+own_scores_2 = { X=0, Y=3, Z=6 }
+game_moves = { 	X = { A=3, B=1, C=2}, -- lose
+                Y = { A=1, B=2, C=3}, -- draw
+                Z = { A=2, B=3, C=1}} -- win
+score = 0
+score_2 = 0
+for line in io.lines() do
+  other, you = string.match(line, "(%a+) (%a+)")
+  score = own_scores[you] + game_scores[you][other] + score
+  score_2 = own_scores_2[you] + game_moves[you][other] + score_2
+--	print(you, own_scores[you], game_scores[you][other], other)
+--	print(you, own_scores_2[you], game_moves[you][other], other)
+end
+print("part 1", score)
+print("part 2", score_2)

12022/02/test

@@ -0,0 +1,3 @@
+A Y
+B X
+C Z

12022/03/03.lua

@@ -0,0 +1,52 @@
+io.input("test")
+io.input("input")
+
+function getPriority(c)
+	if c>='a' and c<='z' then	
+		return string.byte(c) - string.byte('a') + 1
+	else
+		return string.byte(c) - string.byte('A') + 27
+	end
+end
+
+-- for part 1
+local sum = 0
+local linecount = 0
+-- for part 2
+local common = {}
+local sumBadges = 0
+
+for line in io.lines() do
+	local h = {}
+	local i = 0
+	local repeated = nil
+	for c in string.gmatch(line, "%a") do
+		-- part 1
+		if i<#line/2 then
+			h[c] = (h[c] or 0) + 1
+		elseif not repeated and h[c] then
+			repeated = c
+		end
+		i = i + 1
+
+		-- part 2
+		if linecount==0 then
+			common[c] = 1
+		elseif common[c] and linecount==1 then
+			common[c] = 2
+		elseif common[c]==2 then -- 2
+			common[c] = 3
+			sumBadges = sumBadges + getPriority(c)
+		end
+	end
+	-- part 1
+	local priority = getPriority(repeated)
+	sum = sum + priority
+
+	-- part 2
+	if linecount==2 then common = {} end
+	linecount = (linecount + 1)%3
+end
+
+print("part 1", sum)
+print("part 2", sumBadges)

12022/03/test

@@ -0,0 +1,6 @@
+vJrwpWtwJgWrhcsFMMfFFhFp
+jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL
+PmmdzqPrVvPwwTWBwg
+wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn
+ttgJtRGJQctTZtZT
+CrZsJsPPZsGzwwsLwLmpwMDw

12022/04/04.fnl

@@ -0,0 +1,19 @@
+(io.input "input")
+
+(var sum1 0)
+(var sum2 0)
+(each [line (io.lines)]
+  (let [(a b c d) (string.match line "(%d+)-(%d+),(%d+)-(%d+)")
+        ri1 (tonumber a) rf1 (tonumber b) 
+        ri2 (tonumber c) rf2 (tonumber d)]
+      (when (or (and (>= ri1 ri2) (<= rf1 rf2))
+                (and (>= ri2 ri1) (<= rf2 rf1)))
+        (set sum1 (+ sum1 1)))
+      (when (and (>= rf1 ri2) (<= ri1 rf2)) 
+        (set sum2 (+ sum2 1)))))
+;      (when (or (and (>= rf1 ri2) (<= ri1 ri2)) 
+;                (and (>= rf2 ri1) (<= ri2 ri1)))
+;        (set sum2 (+ sum2 1)))))
+
+(print "part 1" sum1)
+(print "part 2" sum2)

12022/04/04.lua

@@ -0,0 +1,36 @@
+io.input("test")
+io.input("input")
+
+local sum = 0
+local sum2 = 0
+for line in io.lines() do
+	local ri1, rf1, ri2, rf2 = string.match(line, "(%d+)-(%d+),(%d+)-(%d+)")
+
+	ri1=tonumber(ri1)
+	rf1=tonumber(rf1)
+	ri2=tonumber(ri2)
+	rf2=tonumber(rf2)
+
+	--[[
+	local r = {}
+	for n in string.gmatch(line,"%d+") do
+		table.insert(r, tonumber(n))
+	end
+	local ri1=r[1]
+	local rf1=r[2]
+	local ri2=r[3]
+	local rf2=r[4]
+	]]
+	-- part 1
+	if (ri1>=ri2 and rf1<=rf2) or (ri2>=ri1 and rf2<=rf1) then
+		sum = sum + 1
+	end
+	-- part 2
+	if (rf1>=ri2 and ri1<=rf2) then-- or (rf2>=ri1 and ri2<=ri1)  then
+		sum2 = sum2 + 1
+	--	print(ri1, rf1, ri2, rf2)
+	end
+end
+
+print("part 1", sum)
+print("part 2", sum2)

12022/04/04_2.fnl

@@ -0,0 +1,19 @@
+(io.input "input")
+
+(var sum1 0)
+(var sum2 0)
+(each [line (io.lines)]
+  (let [pattern "(%d+)-(%d+),(%d+)-(%d+)"
+    [ri1 rf1 ri2 rf2] 
+    (icollect [_ n (-> line (string.match pattern) (table.pack) (ipairs))]
+; (-> ...) equivalent to:
+;        (ipairs (table.pack (string.match line pattern)))] 
+      (tonumber n))]
+      (when (or (and (>= ri1 ri2) (<= rf1 rf2))
+                (and (>= ri2 ri1) (<= rf2 rf1)))
+        (set sum1 (+ sum1 1)))
+      (when (and (>= rf1 ri2) (<= ri1 rf2)) 
+        (set sum2 (+ sum2 1)))))
+
+(print "part 1" sum1)
+(print "part 2" sum2)

12022/04/test

@@ -0,0 +1,6 @@
+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8

12022/05/05.lua

@@ -0,0 +1,74 @@
+io.input("test")
+io.input("input")
+
+stacks = {}
+stacks2 = {}
+instructions = {}
+count = 0
+
+function printStacks()
+  for i,stack in ipairs(stacks) do
+    local s = ""
+    for _,j in ipairs(stack) do
+      s = s .. j
+    end
+    print(i, s)
+  end
+end
+
+-- parsing
+for line in io.lines() do
+  if string.find(line, "%[%a%]") then
+    local nstacks =  #line//4 + 1  -- 1 5 9
+    for i = 1,nstacks do
+      if count == 0 then
+        stacks[i] = {}
+        stacks2[i] = {}
+      end
+      local index = 1 + (i-1)*4 -- 1, 5, 9
+      local s = string.sub(line, index, index+3)
+      local t = string.match(s, "%[(%a)%]")
+      table.insert( stacks[i], 1, t )
+      table.insert( stacks2[i], 1, t )
+    end
+  elseif string.find(line, "^move") then
+    local pattern = "^move (%d+) from (%d+) to (%d+)$"
+    local tt = table.pack(string.match(line, pattern))
+    local t = {}
+    for j, v in ipairs(tt) do t[j] = tonumber(v) end
+    table.insert(instructions, t)
+  end
+  count = count + 1
+end
+
+-- moves
+for i, t in ipairs(instructions) do
+  q, src, dst = table.unpack(t)
+  -- part 1
+  for n = 1,q do
+    local crate = table.remove( stacks[src] )
+    table.insert( stacks[dst], crate )
+  end
+
+  -- part 2
+  local crates = {}
+  for n = 1,q do
+    crates[q-n+1] = table.remove( stacks2[src] )
+  end
+  for n = 1,q do
+    table.insert( stacks2[dst], crates[n] )
+  end
+end
+
+-- result
+local result = ""
+for _, stack in ipairs(stacks) do
+  result = result .. stack[#stack]
+end
+print("part 1", result)
+
+result = ""
+for _, stack in ipairs(stacks2) do
+  result = result .. stack[#stack]
+end
+print("part 2", result)

12022/05/05_part2.lua

@@ -0,0 +1,63 @@
+io.input("test")
+io.input("input")
+
+stacks = {}
+instructions = {}
+count = 0
+
+function printStacks()
+  for i,stack in ipairs(stacks) do
+    local s = ""
+    for _,j in ipairs(stack) do
+      s = s .. j
+    end
+    print(i, s)
+  end
+end
+
+-- parsing
+for line in io.lines() do
+  if string.find(line, "%[%a%]") then
+    local nstacks =  #line//4 + 1  -- 1 5 9
+    print(nstacks)
+    for i = 1,nstacks do
+      if count == 0 then
+        stacks[i] = {}
+      end
+      local index = 1 + (i-1)*4 -- 1, 5, 9
+      local s = string.sub(line, index, index+3)
+      local t = string.match(s, "%[(%a)%]")
+      table.insert( stacks[i], 1, t )
+    end
+  elseif string.find(line, "^move") then
+    local pattern = "^move (%d+) from (%d+) to (%d+)$"
+    local t = table.pack(string.match(line, pattern))
+    table.insert(instructions,t)
+  end
+  count = count + 1
+end
+
+-- moves
+for i, t in ipairs(instructions) do
+  local tt = {}
+  for j, v in ipairs(t) do tt[j] = tonumber(v) end
+
+  q, src, dst = table.unpack(tt)
+  local crates = {}
+  for n = 1,q do
+    crates[q-n+1] = table.remove( stacks[src] )
+  end
+  for n = 1,q do
+    table.insert( stacks[dst], crates[n] )
+  end
+end
+
+printStacks()
+-- result
+local result = ""
+for _, stack in ipairs(stacks) do
+  result = result .. stack[#stack]
+end
+
+print("part 2", result)
+

12022/05/test

@@ -0,0 +1,9 @@
+    [D]    
+[N] [C]    
+[Z] [M] [P]
+ 1   2   3 
+
+move 1 from 2 to 1
+move 3 from 1 to 3
+move 2 from 2 to 1
+move 1 from 1 to 2

12022/06/06.fnl

@@ -0,0 +1,16 @@
+(io.input "test")
+(λ repeats [s]
+  (let [chars {}]
+    (for [i 1 (length s)]
+      (let [c (string.sub s i i)]
+        (if (. chars c) true (tset chars c true)))))
+  false)
+
+(λ end-of-marker [s n] 
+  (for [i 1 (length s)]
+    (let [window (string.sub s i (+ i (- n 1)))]
+      (print window))))
+
+(end-of-marker (io.read "a") 4)  
+
+(print (repeats "aacd"))

12022/06/06.lua

@@ -0,0 +1,25 @@
+io.input("test")
+io.input("input")
+local s = io.read("a")
+
+function endOfMarker( n ) -- n is the window size
+  local i=1
+  repeat
+    local window = string.sub(s,i,i+n-1)
+    local repeats = false
+    local chars = {}
+    for j=1,n do
+      local c = string.sub(window,j,j)
+      if chars[c] then 
+        repeats = true
+        break
+      else chars[c] = true 
+      end
+    end
+    i = i + 1
+  until not repeats or i>#s
+  return i+n-2
+end
+
+print("part 1", endOfMarker(4))
+print("part 2", endOfMarker(14))

12022/06/test

@@ -0,0 +1 @@
+mjqjpqmgbljsphdztnvjfqwrcgsmlb

12022/07/07.lua

@@ -0,0 +1,92 @@
+io.input("test")
+io.input("input")
+
+function createDir( dirname )
+  return { name = dirname, children = {}, localsize = 0}
+end
+
+function insertDirIntoWD( dirname )
+  -- if it already exists, return it
+  for _, d in ipairs( wd.children ) do
+    if d.name == dirname then return d end
+  end 
+--  print("inserting", dirname, "into", wd.name)
+  -- create it otherwise
+  local newdir = createDir(dirname)
+  table.insert( wd.children, newdir )
+  table.insert( dirs, newdir )
+  return newdir
+end
+
+-- initialize
+root = createDir("/") 
+dirs = {root}
+stack = {root}
+wd = root -- working directory
+
+local listing = false
+for line in io.lines() do
+  if listing then
+    if string.find(line, "^%$") then
+      listing = false
+    else -- listing
+      local pattern = "^(.+) (.+)$"
+      local info, name = string.match( line, pattern )
+      if info == "dir" then
+        insertDirIntoWD( name )
+      else -- file
+        local size = tonumber(info)
+        wd.localsize = wd.localsize + size
+      end
+    end
+  end -- if listing
+
+  if not listing then
+    if string.find(line, "^%$ ls") then
+      listing = true
+    else -- change directory
+      local dirname = string.match(line, "^%$ cd (.+)$")
+      if dirname == "/" then
+        wd = root
+        stack = {root}
+      elseif dirname == ".." then
+        wd = table.remove( stack ) -- pop from stack
+      else -- go to named dir
+        table.insert( stack, wd ) -- push wd into stack
+        wd = insertDirIntoWD( dirname )
+      end -- if dirname
+    end -- if $ ls
+  end -- if not listing
+
+end -- for line
+
+function totalSize( dir )
+  local sum = dir.localsize
+  for i, d in ipairs( dir.children ) do
+    sum = sum + totalSize( d )
+  end
+  return sum
+end
+
+-- part 1
+local result1 = 0
+-- part 2
+local total = totalSize(dirs[1])
+local unused = 70000000 - total
+local needed = 30000000 - unused
+local minGreaterThanNeeded = total
+
+for i, d in ipairs(dirs) do
+  local size = totalSize(d)
+  -- part 1
+  if size <= 100000 then
+    result1 = result1 + size
+  end
+  -- part 2
+  if size >= needed and size < minGreaterThanNeeded then
+    minGreaterThanNeeded = size
+  end
+end
+
+print("part 1", result1)
+print("part 2", minGreaterThanNeeded)

12022/07/07_upgrade.lua

@@ -0,0 +1,94 @@
+io.input("test")
+io.input("input")
+
+function createDir( dirname )
+  return { name = dirname, children = {}, localsize = 0 }
+end
+
+function insertDirIntoWD( dirname )
+  -- if it already exists, return it
+  for _, d in ipairs( wd.children ) do
+    if d.name == dirname then return d end
+  end 
+--  print("inserting", dirname, "into", wd.name)
+  -- create it otherwise
+  local newdir = createDir(dirname)
+  table.insert( wd.children, newdir )
+  table.insert( dirs, newdir )
+  return newdir
+end
+
+-- initialize
+root = createDir("/") 
+dirs = {root}
+stack = {root}
+wd = root -- working directory
+
+local listing = false
+for line in io.lines() do
+  if listing then
+    if string.find(line, "^%$") then
+      listing = false
+    else -- listing
+      local pattern = "^(.+) (.+)$"
+      local info, name = string.match( line, pattern )
+      if info == "dir" then
+        insertDirIntoWD( name )
+      else -- file
+        local size = tonumber(info)
+        wd.localsize = wd.localsize + size
+      end
+    end
+  end -- if listing
+
+  if not listing then
+    if string.find(line, "^%$ ls") then
+      listing = true
+    else -- change directory
+      local dirname = string.match(line, "^%$ cd (.+)$")
+      if dirname == "/" then
+        wd = root
+        stack = {root}
+      elseif dirname == ".." then
+        wd = table.remove( stack ) -- pop from stack
+      else -- go to named dir
+        table.insert( stack, wd ) -- push wd into stack
+        wd = insertDirIntoWD( dirname )
+      end -- if dirname
+    end -- if $ ls
+  end -- if not listing
+
+end -- for line
+
+function totalSize( dir )
+  if dir.totalsize then return dir.totalsize end
+  local sum = dir.localsize
+  for i, d in ipairs( dir.children ) do
+    sum = sum + totalSize( d )
+  end
+  dir.totalsize = sum
+  return sum
+end
+
+-- part 1
+local result1 = 0
+-- part 2
+local total = totalSize(dirs[1])
+local unused = 70000000 - total
+local needed = 30000000 - unused
+local minGreaterThanNeeded = total
+
+for i, d in ipairs(dirs) do
+  local size = totalSize(d)
+  -- part 1
+  if size <= 100000 then
+    result1 = result1 + size
+  end
+  -- part 2
+  if size >= needed and size < minGreaterThanNeeded then
+    minGreaterThanNeeded = size
+  end
+end
+
+print("part 1", result1)
+print("part 2", minGreaterThanNeeded)

12022/07/test

@@ -0,0 +1,25 @@
+$ cd /
+$ ls
+dir a
+14848514 b.txt
+8504156 c.dat
+dir d
+$ cd a
+$ ls
+dir e
+29116 f
+2557 g
+62596 h.lst
+$ cd e
+$ ls
+584 i
+$ cd ..
+$ cd ..
+$ cd d
+$ ls
+4060174 j
+8033020 d.log
+5626152 d.ext
+7214296 k
+$ cd ..
+$ cd a

12022/08/08.lua

@@ -0,0 +1,98 @@
+io.input("test")
+io.input("input")
+
+function addTree( r, c, height )
+  local visible = nil
+  if r==1 or c==1 or r==n or c==n then
+    visible = true
+  end
+  local tree = { h = height, v = visible, s = 1 }
+  trees[r][c] = tree
+  return tree
+end
+
+trees = {}
+n = 0
+local row = 1
+for line in io.lines() do
+  n = #line
+  local col = 1
+  trees[row] = {}
+  for height in string.gmatch(line, "%d") do
+    local tree = addTree( row, col, height )
+    if row>1 and col>1 then
+      local allLess = true
+      local s = 0
+      for r=row-1,1,-1 do
+        s = s+1
+        if trees[r][col].h >= tree.h then
+          allLess = false
+          break
+        end
+      end
+      if allLess then tree.v = true end
+      tree.s = s*tree.s
+
+      allLess = true
+      s = 0
+      for c=col-1,1,-1 do
+        s = s + 1
+        if trees[row][c].h >= tree.h then
+          allLess = false
+          break
+        end
+      end
+      if allLess then tree.v = true end
+      tree.s = s*tree.s
+    end
+    col = col + 1
+  end
+  row = row + 1
+end
+
+-- second pass, other direction
+for row = n-1, 2, -1 do
+  for col = n-1, 2, -1 do
+    local tree = trees[row][col]
+    local allLess = true
+    local s = 0
+    for r=row+1,n do
+      s = s + 1
+      if trees[r][col].h >= tree.h then
+        allLess = false
+        break
+      end
+    end
+    if allLess then tree.v = true end
+    tree.s = tree.s*s
+
+    allLess = true
+    s = 0
+    for c=col+1,n do
+      s = s + 1
+      if trees[row][c].h >= tree.h then
+        allLess = false
+        break
+      end
+    end
+    if allLess then tree.v = true end
+    tree.s = tree.s*s
+
+  end
+end
+
+local sum = 0
+local maxscore = 0
+for i, row in ipairs(trees) do
+  for j, tree in ipairs(row) do
+ -- part 1
+    if tree.v then sum = sum + 1 end
+ -- part 2
+    if tree.s > maxscore and i>1 and i<n and j>1 and j<n then 
+      maxscore = tree.s 
+    end
+  end
+end
+
+print("part 1", sum )
+print("part 2", maxscore )

12022/08/test

@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390

12022/09/09.lua

@@ -0,0 +1,56 @@
+io.input("test")
+io.input("input")
+
+
+function pos2index( pos )
+  return pos.x*10000 + pos.y
+end
+
+function constrain( n, min, max )
+  local min = min or -1
+  local max = max or 1
+  if n < min then return min
+  elseif n > max then return max
+  else return n
+  end
+end
+
+
+local head = { x=1, y=1 }
+local tail = { x=1, y=1 }
+local visited = { [pos2index(tail)] = true }
+
+for line in io.lines() do
+  local dir, q = string.match(line, "^(%a) (%d+)$")
+  q = tonumber(q)
+  for step = 1,q do
+    if dir == "R" then
+      head.x = head.x + 1
+    elseif dir == "L" then
+      head.x = head.x - 1
+    elseif dir == "U" then
+      head.y = head.y + 1
+    elseif dir == "D" then
+      head.y = head.y - 1
+    end
+
+    local dif = { x=head.x-tail.x, y=head.y-tail.y }
+    if dif.x == 0 and math.abs(dif.y) > 1 then
+      tail.y = tail.y + constrain(dif.y)
+    elseif dif.y == 0 and math.abs(dif.x) > 1 then
+      tail.x = tail.x + constrain(dif.x)
+    elseif math.abs(dif.x)>1 or math.abs(dif.y)>1 then
+      tail.y = tail.y + constrain(dif.y)
+      tail.x = tail.x + constrain(dif.x)
+    end
+    print( tail.x, tail.y, head.x, head.y, dif.x, dif.y)
+    visited[ pos2index(tail) ] = true
+  end
+end
+
+local result = 0
+for k, v in pairs(visited) do
+  print(k)
+  result = result + 1
+end
+print("part 1", result)

12022/09/09_2.lua

@@ -0,0 +1,89 @@
+io.input("test2")
+io.input("input")
+
+function pos2index( pos )
+  return pos.x*10000 + pos.y
+end
+
+function constrain( n, min, max )
+  -- returns converted n, and if it was converted
+  local min = min or -1
+  local max = max or 1
+  if n < min then return min, true
+  elseif n > max then return max, true
+  else return n, false
+  end
+end
+
+local head = { x=1, y=1 }
+local n = 9
+local tail = {}
+for i=1,n do tail[i] = { x=1, y=1 } end
+local visitedP1 = { [pos2index(tail[1])] = true }
+local visitedP2 = { [pos2index(tail[n])] = true }
+local resultP1 = 1
+local resultP2 = 1
+
+for line in io.lines() do
+  local dir, q = string.match(line, "^(%a) (%d+)$")
+  q = tonumber(q)
+  for step = 1,q do
+    if dir == "R" then
+      head.x = head.x + 1
+    elseif dir == "L" then
+      head.x = head.x - 1
+    elseif dir == "U" then
+      head.y = head.y + 1
+    elseif dir == "D" then
+      head.y = head.y - 1
+    end
+
+    -- loop through tails
+    for i=1,n do
+      local h = head
+      if i>1 then h = tail[i-1] end
+      local t = tail[i]
+      local dif = { x=h.x-t.x, y=h.y-t.y }
+      -- gx, gy indicate if the abs diff was greater than 1
+      local dx, gx = constrain(dif.x) 
+      local dy, gy = constrain(dif.y) 
+      if dif.x == 0 and gy then -- vertical
+        t.y = t.y + dy
+      elseif dif.y == 0 and gx then -- horizontal
+        t.x = t.x + dx
+      elseif gx or gy then -- diagonal further away
+        t.y = t.y + dy
+        t.x = t.x + dx
+      end
+    end
+
+    -- part 1
+    local index = pos2index(tail[1])
+    if not visitedP1[index] then
+      visitedP1[index] = true
+      resultP1 = resultP1 + 1
+    end
+    -- part 2
+    local index = pos2index(tail[n])
+    if not visitedP2[index] then
+      visitedP2[index] = true
+      resultP2 = resultP2 + 1
+    end
+--    visitedP1[ pos2index(tail[1]) ] = true
+--    visitedP2[ pos2index(tail[n]) ] = true
+  end
+end
+print("part 1", resultP1)
+print("part 2", resultP2)
+
+local result = 0
+for k, v in pairs(visitedP1) do
+  result = result + 1
+end
+print("part 1", result, resultP1)
+
+local result = 0
+for k, v in pairs(visitedP2) do
+  result = result + 1
+end
+print("part 2", result, resultP2)