claudinec
diff --git a/‎aoc2020.ipynb
Lines changed: 67 additions & 0 deletions b/‎aoc2020.ipynb
Lines changed: 67 additions & 0 deletions
@@ -365,6 +365,73 @@
     "print(valid)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Day 5\n",
+    "\n",
+    "What is the highest seat ID on a boarding pass?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 128,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "813\n"
+     ]
+    }
+   ],
+   "source": [
+    "seats = []\n",
+    "\n",
+    "# Assign seat IDs.\n",
+    "with open('day05-input.txt') as input_file_05:\n",
+    "    for line in input_file_05:\n",
+    "        # They're just binary numbers.\n",
+    "        row_s = line[0:7]\n",
+    "        row_i = int(row_s.replace('F', '0').replace('B', '1'), base=2)\n",
+    "        col_s = line[7:10]\n",
+    "        col_i = int(col_s.replace('L', '0').replace('R', '1'), base=2)\n",
+    "        seats.append(row_i * 8 + col_i)\n",
+    "\n",
+    "# Find the highest seat ID.\n",
+    "print(max(seats))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Find the missing seat ID."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 137,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "611 613\n"
+     ]
+    }
+   ],
+   "source": [
+    "seats.sort()\n",
+    "for i in seats:\n",
+    "    if seats[i+1] > seats[i] + 1:\n",
+    "        print(seats[i], seats[i+1])\n",
+    "        break"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,