{ "cells": [ { "cell_type": "code", "execution_count": 18, "metadata": {}, "outputs": [], "source": [ "#input = r'''0 1 10 99 999'''\n", "#input = r'''125 17'''\n", "input = r'''475449 2599064 213 0 2 65 5755 51149'''\n", "\n", "stones = [int(x) for x in input.split()]" ] }, { "cell_type": "code", "execution_count": 19, "metadata": {}, "outputs": [], "source": [ "from functools import lru_cache\n", "\n", "@lru_cache(maxsize=None)\n", "def step(stone,steps):\n", " if steps == 1:\n", " if stone == 0:\n", " return 1\n", " elif (tx_stone := str(stone)) and len(tx_stone) %2 == 0:\n", " return 2\n", " else:\n", " return 1\n", " else:\n", " if stone == 0:\n", " return step(1,steps-1)\n", " elif (tx_stone := str(stone)) and len(tx_stone) %2 == 0:\n", " half = len(tx_stone)//2\n", " left = int(tx_stone[:half])\n", " right = int(tx_stone[half:])\n", " x_left = step(left,steps-1)\n", " x_right = step(right,steps-1)\n", " return x_left + x_right\n", " else:\n", " return(step(stone*2024,steps-1))\n" ] }, { "cell_type": "code", "execution_count": 20, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "193269" ] }, "execution_count": 20, "metadata": {}, "output_type": "execute_result" } ], "source": [ "sum([step(stone,25) for stone in stones])" ] }, { "cell_type": "code", "execution_count": 21, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "228449040027793" ] }, "execution_count": 21, "metadata": {}, "output_type": "execute_result" } ], "source": [ "sum([step(stone,75) for stone in stones])" ] } ], "metadata": { "kernelspec": { "display_name": "advent", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.13.0" } }, "nbformat": 4, "nbformat_minor": 2 }