149 lines
4.3 KiB
Plaintext
149 lines
4.3 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": 72,
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"metadata": {},
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"outputs": [],
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"source": [
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"import networkx as nx\n",
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"\n",
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"# Define directions and corresponding movements\n",
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"DIRECTIONS = ['N', 'E', 'S', 'W']\n",
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"MOVEMENTS = {\n",
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" 'N': (0, -1), # Move up\n",
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" 'E': (1, 0), # Move right\n",
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" 'S': (0, 1), # Move down\n",
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" 'W': (-1, 0) # Move left\n",
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"}\n",
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"\n",
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"# Parse the ASCII map into a graph with movement and turning costs\n",
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"def parse_ascii_map_with_costs(ascii_map):\n",
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" graph = nx.DiGraph() # Directed graph for handling edge weights\n",
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" rows = ascii_map.strip().split(\"\\n\")\n",
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" height, width = len(rows), len(rows[0])\n",
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"\n",
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" start, end = None, None\n",
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" for y, row in enumerate(rows):\n",
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" for x, char in enumerate(row):\n",
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" if char != '#': # Walkable space\n",
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" for direction in DIRECTIONS: # Add a node for each direction\n",
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" graph.add_node((x, y, direction))\n",
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" if char == 'S': # Starting point\n",
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" start = (x, y, 'E') # Assume starting direction is North\n",
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" elif char == 'E': # Ending point\n",
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" end = (x, y)\n",
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"\n",
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" # Add edges for moving forward\n",
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" for direction in DIRECTIONS:\n",
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" dx, dy = MOVEMENTS[direction]\n",
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" nx_new, ny_new = x + dx, y + dy\n",
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" if 0 <= nx_new < width and 0 <= ny_new < height and rows[ny_new][nx_new] != '#':\n",
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" if rows[ny_new][nx_new] == 'E':\n",
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" graph.add_edge((x, y, direction), (nx_new, ny_new), weight=1)\n",
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" else:\n",
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" graph.add_edge((x, y, direction), (nx_new, ny_new, direction), weight=1)\n",
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"\n",
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" # Add edges for turning (clockwise and counterclockwise)\n",
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" for i, direction in enumerate(DIRECTIONS):\n",
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" next_dir = DIRECTIONS[(i + 1) % 4] # Clockwise\n",
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" prev_dir = DIRECTIONS[(i - 1) % 4] # Counterclockwise\n",
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" graph.add_edge((x, y, direction), (x, y, next_dir), weight=1000)\n",
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" graph.add_edge((x, y, direction), (x, y, prev_dir), weight=1000)\n",
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"\n",
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" return graph, start, end"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 73,
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"metadata": {},
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"outputs": [],
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"source": [
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"with open('input','r') as infile:\n",
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" ascii_map = infile.read()\n",
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"\n",
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"# Parse the map and solve\n",
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"graph, start, end = parse_ascii_map_with_costs(ascii_map)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 74,
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"metadata": {},
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"outputs": [],
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"source": [
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"shortestpath = nx.shortest_path(graph,start,end,weight='weight')\n",
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"shortestpath_cost = nx.shortest_path_length(graph,start,end,weight='weight')"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 75,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"135512\n"
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]
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}
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],
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"source": [
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"print(shortestpath_cost)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 76,
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"541"
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]
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},
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"execution_count": 76,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"\n",
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"\n",
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"paths = nx.all_shortest_paths(graph,source=start,target=end,weight='weight')\n",
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"visited_nodes = set()\n",
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"\n",
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"for path in paths:\n",
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" for grid_node in path:\n",
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" visited_nodes.add((grid_node[0],grid_node[1]))\n",
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"\n",
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"len(visited_nodes)"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "advent",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.13.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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