Add day 16

d16.lua

@@ -0,0 +1,75 @@
+signal = {}
+file = io.open(arg[1])
+for num in file:read("a"):gmatch("%d") do
+    table.insert(signal, tonumber(num))
+end
+file:close()
+
+function calc(signal, num)
+    local fin = #signal
+    local cur = num
+    local val = 0
+    while cur <= fin do
+        for _, x in ipairs({1, 0, -1, 0}) do
+            if x == 0 then
+                cur = cur + num
+            else
+                local cur_val = 0
+                for i = 1, num do
+                    cur_val = cur_val + signal[cur]
+                    cur = cur + 1
+                    if cur > fin then
+                        break
+                    end
+                end
+                val = val + cur_val * x
+            end
+            if cur > fin then
+                break
+            end
+        end
+    end
+
+    return math.abs(val) % 10
+end
+
+function calc_dumb_p2(signal, offset)
+    local val = 0
+    for i = #signal, offset, -1 do
+        val = (val + signal[i]) % 10
+        signal[i] = val
+    end
+end
+
+function signal_tostring(signal, start, len)
+    local str = ""
+    for i = start, len do
+        str = str .. string.format("%d", signal[i])
+    end
+    return str
+end
+
+offset = signal[1] * (10 ^ 6) + signal[2] * (10 ^ 5) + signal[3] * (10 ^ 4) + signal[4] * (10 ^ 3) + signal[5] * (10 ^ 2) + signal[6] * (10 ^ 1) + signal[7]
+signal_p2 = {}
+for i = 1, 10000 do
+    for i = 1, #signal do
+        table.insert(signal_p2, signal[i])
+    end
+end
+print(offset)
+offset = offset % #signal_p2
+print(offset)
+
+for i = 1, 100 do
+    for i = 1, #signal do
+        signal[i] = calc(signal, i)
+    end
+end
+
+print("Part 1:", signal_tostring(signal, 1, 8))
+
+for i = 1, 100 do
+    calc_dumb_p2(signal_p2, offset)
+end
+
+print("Part 2:", signal_tostring(signal_p2, offset + 1, offset + 8))

d16_input.txt

@@ -0,0 +1 @@
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