From c6226208a4e00d346b35cd7043a48d65bb7779ef Mon Sep 17 00:00:00 2001
From: mid-kid <esteve.varela@gmail.com>
Date: Thu, 19 Dec 2019 11:56:40 +0100
Subject: [PATCH] Add day 19

---
 d19.lua       | 244 ++++++++++++++++++++++++++++++++++++++++++++++++++
 d19_input.txt |   1 +
 2 files changed, 245 insertions(+)
 create mode 100644 d19.lua
 create mode 100644 d19_input.txt

diff --git a/d19.lua b/d19.lua
new file mode 100644
index 0000000..83c324d
--- /dev/null
+++ b/d19.lua
@@ -0,0 +1,244 @@
+function get_param(state, arg)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    if #state.mem < state.pos + arg then
+        print(string.format("Error: Opcode too short at end of memory: %d", state.pos))
+        os.exit(false)
+    end
+    local arg = state.mem[state.pos + arg]
+    if param_mode == 0 then
+        arg = arg + 1
+    elseif param_mode == 2 then
+        arg = arg + state.relbase
+    end
+    return arg
+end
+
+function read_mem(state, arg)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    local arg = get_param(state, arg)
+    if param_mode == 1 then
+        return arg
+    end
+    arg = state.mem[arg]
+    if not arg then
+        return 0
+    end
+    return arg
+end
+
+function write_mem(state, arg, val)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    local arg = get_param(state, arg)
+    if param_mode == 1 then
+        print(string.format("Error: Invalid inmediate write: %d", arg))
+    end
+    state.mem[arg] = val
+end
+
+function interpret(state)
+    if not state.mem then
+        state.mem = state
+    end
+    if not state.pos then
+        state.pos = 1
+        state.relbase = 1
+    end
+    if not state.input then
+        state.input = input_stdin
+    end
+    if not state.output then
+        state.output = output_stdout
+    end
+
+    while true do
+        if #state.mem < state.pos then
+            print(string.format("Instruction pointer ran off of memory"))
+            os.exit(false)
+        end
+
+        local opcode = state.mem[state.pos] % 100
+        local instr_size = 1
+
+        if opcode == 1 then
+            write_mem(state, 3, read_mem(state, 1) + read_mem(state, 2))
+            instr_size = 4
+        elseif opcode == 2 then
+            write_mem(state, 3, read_mem(state, 1) * read_mem(state, 2))
+            instr_size = 4
+        elseif opcode == 3 then
+            local val = state.input()
+            if not val then return true end
+            write_mem(state, 1, val)
+            instr_size = 2
+        elseif opcode == 4 then
+            state.output(read_mem(state, 1))
+            instr_size = 2
+        elseif opcode == 5 then
+            instr_size = 3
+            if read_mem(state, 1) ~= 0 then
+                state.pos = read_mem(state, 2) + 1
+                instr_size = 0
+            end
+        elseif opcode == 6 then
+            instr_size = 3
+            if read_mem(state, 1) == 0 then
+                state.pos = read_mem(state, 2) + 1
+                instr_size = 0
+            end
+        elseif opcode == 7 then
+            write_mem(state, 3, read_mem(state, 1) < read_mem(state, 2) and 1 or 0)
+            instr_size = 4
+        elseif opcode == 8 then
+            write_mem(state, 3, read_mem(state, 1) == read_mem(state, 2) and 1 or 0)
+            instr_size = 4
+        elseif opcode == 9 then
+            state.relbase = state.relbase + read_mem(state, 1)
+            instr_size = 2
+        elseif opcode == 99 then
+            return false
+        else
+            print(string.format("Error: Invalid opcode %d at %d", opcode, state.pos - 1))
+            os.exit(false)
+        end
+
+        state.pos = state.pos + instr_size
+    end
+end
+
+function input_stdin()
+    io.stdout:write("> ")
+    return io.stdin:read("n")
+end
+
+function output_stdout(val)
+    io.stdout:write(val)
+    io.stdout:write("\n")
+end
+
+function input_array(array)
+    function inner()
+        return table.remove(array, 1)
+    end
+    return inner
+end
+
+function output_array(array)
+    function inner(val)
+        table.insert(array, val)
+    end
+    return inner
+end
+
+file = io.open(arg[1])
+program = {}
+for num in string.gmatch(file:read(), "(-?%d+),?") do
+    table.insert(program, tonumber(num))
+end
+file:close()
+
+--interpret(program)
+
+--file = {}
+--for line in io.lines(arg[1]) do
+    --fline = {}
+    --for char in line:gmatch(".") do
+        --if char == "." then
+            --table.insert(fline, 0)
+        --else
+            --table.insert(fline, 1)
+        --end
+    --end
+    --table.insert(file, fline)
+--end
+
+result_p1 = 0
+angles_low = {}
+angles_high = {}
+for y = 0, 49 do
+--for y = 0, 34 do
+    current = 0
+    for x = 0, 49 do
+    --for x = 0, 34 do
+        output = {}
+        interpret({mem={table.unpack(program)}, input=input_array({x, y}), output=output_array(output)})
+        --output = {file[y + 1][x + 1]}
+        result_p1 = result_p1 + output[1]
+        if current ~= output[1] then
+            current = output[1]
+            if current == 1 then
+                table.insert(angles_low, math.atan(y + 0.5, x + 0.5))
+            else
+                table.insert(angles_high, math.atan(y + 0.5, x + 0.5))
+            end
+        end
+    end
+end
+print("Part 1:", result_p1)
+
+p1 = {x=1, y=1}
+p2 = {x=1, y=1}
+
+while (p2.x - p1.x) < 99 or (p1.y - p2.y) < 99 do
+    if (p2.x - p1.x) < 99 then
+        p2.x = p1.x + 99
+        while true do
+            output = {}
+            interpret({mem={table.unpack(program)}, input=input_array({p2.x, p2.y}), output=output_array(output)})
+            if output[1] == 1 then
+                break
+            end
+            p2.y = p2.y + 1
+        end
+    end
+    if (p1.y - p2.y) < 99 then
+        p1.y = p2.y + 99
+        while true do
+            output = {}
+            interpret({mem={table.unpack(program)}, input=input_array({p1.x, p1.y}), output=output_array(output)})
+            if output[1] == 1 then
+                break
+            end
+            p1.x = p1.x + 1
+        end
+    end
+end
+
+print("Part 2:", p1.x * 10000 + p2.y)
+
+
+-- I tried to do this using the law of cosines and it works for the example, but not for the "real" thing...
+
+function mean(table)
+    local sum = 0
+    for _, x in ipairs(table) do
+        sum = sum + x
+    end
+    return sum / #table
+end
+
+angle_low = mean(angles_low)
+angle_high = mean(angles_high)
+angle_rect = -math.pi * 1 / 4
+
+print(angle_low, angle_high, angle_rect)
+
+angle_alpha = angle_low - angle_high
+angle_beta = math.pi - (angle_low - angle_rect)
+angle_gamma = angle_high - angle_rect
+
+print(angle_alpha, angle_beta, angle_gamma, (angle_alpha + angle_beta + angle_gamma) / math.pi)
+
+length_a = math.sqrt((99 ^ 2) + (99 ^ 2))
+--length_a = math.sqrt((9 ^ 2) + (9 ^ 2))
+length_b = length_a * math.sin(angle_beta) / math.sin(angle_alpha)
+length_c = length_a * math.sin(angle_gamma) / math.sin(angle_alpha)
+
+pos_low = {x=math.cos(angle_low) * length_c, y=math.sin(angle_low) * length_c}
+pos_high = {x=math.cos(angle_high) * length_b, y=math.sin(angle_high) * length_b}
+print(pos_low.x, pos_low.y, pos_high.x, pos_high.y)
+print(angle_rect + math.pi, math.atan(pos_low.y - pos_high.y, pos_low.x - pos_high.x))
+
+pos_x = math.ceil(pos_low.x - 0.5)
+pos_y = math.ceil(pos_high.y - 0.5)
+
+print("Part 2:", pos_x * 10000 + pos_y)
diff --git a/d19_input.txt b/d19_input.txt
new file mode 100644
index 0000000..669809d
--- /dev/null
+++ b/d19_input.txt
@@ -0,0 +1 @@
+109,424,203,1,21102,11,1,0,1106,0,282,21102,18,1,0,1105,1,259,1202,1,1,221,203,1,21102,31,1,0,1106,0,282,21101,38,0,0,1106,0,259,21002,23,1,2,22102,1,1,3,21102,1,1,1,21102,1,57,0,1105,1,303,2101,0,1,222,21002,221,1,3,20101,0,221,2,21101,0,259,1,21102,1,80,0,1105,1,225,21102,1,8,2,21101,91,0,0,1106,0,303,1202,1,1,223,21002,222,1,4,21102,1,259,3,21101,225,0,2,21101,225,0,1,21101,0,118,0,1105,1,225,21001,222,0,3,21101,0,48,2,21102,133,1,0,1106,0,303,21202,1,-1,1,22001,223,1,1,21102,1,148,0,1105,1,259,1201,1,0,223,20101,0,221,4,21001,222,0,3,21101,0,6,2,1001,132,-2,224,1002,224,2,224,1001,224,3,224,1002,132,-1,132,1,224,132,224,21001,224,1,1,21102,1,195,0,105,1,108,20207,1,223,2,21001,23,0,1,21101,-1,0,3,21101,0,214,0,1105,1,303,22101,1,1,1,204,1,99,0,0,0,0,109,5,2101,0,-4,249,21201,-3,0,1,22102,1,-2,2,21202,-1,1,3,21102,1,250,0,1106,0,225,21201,1,0,-4,109,-5,2106,0,0,109,3,22107,0,-2,-1,21202,-1,2,-1,21201,-1,-1,-1,22202,-1,-2,-2,109,-3,2106,0,0,109,3,21207,-2,0,-1,1206,-1,294,104,0,99,22101,0,-2,-2,109,-3,2106,0,0,109,5,22207,-3,-4,-1,1206,-1,346,22201,-4,-3,-4,21202,-3,-1,-1,22201,-4,-1,2,21202,2,-1,-1,22201,-4,-1,1,22102,1,-2,3,21101,0,343,0,1105,1,303,1105,1,415,22207,-2,-3,-1,1206,-1,387,22201,-3,-2,-3,21202,-2,-1,-1,22201,-3,-1,3,21202,3,-1,-1,22201,-3,-1,2,22101,0,-4,1,21101,384,0,0,1106,0,303,1106,0,415,21202,-4,-1,-4,22201,-4,-3,-4,22202,-3,-2,-2,22202,-2,-4,-4,22202,-3,-2,-3,21202,-4,-1,-2,22201,-3,-2,1,21201,1,0,-4,109,-5,2106,0,0