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Author: DeveloperYard

dijkstra-review/dijkstra_review_21_02_03_heapq.ipynb

@@ -0,0 +1,72 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c14e8ac8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from collections import heapq\n",
+    "\n",
+    "h = []\n",
+    "INF = int(1e9)\n",
+    "n, m = map(int, input().split())\n",
+    "start = int(input())\n",
+    "\n",
+    "graph = [[] for i in range(n+1)]\n",
+    "# 노드에 연결되어 있는 노드에 대한 정보를 담는 리스트를 만들기\n",
+    "distance = [INF]*(n+1)\n",
+    "\n",
+    "for _ in range(m):\n",
+    "    a, b, c = map(int, input().split())\n",
+    "    graph[a].append((b, c))\n",
+    "    \n",
+    "def dijkstra(start):\n",
+    "    h = []\n",
+    "    heapq.heappush(h, (0, start))\n",
+    "    distance[start] = 0\n",
+    "    \n",
+    "    while h:\n",
+    "        dist, now = heapq.heappop(h)\n",
+    "        \n",
+    "        if distance[now] < dist:\n",
+    "            continue\n",
+    "        for i in graph[now]:\n",
+    "            cost = dist + i[1]\n",
+    "            if cost < distance[i[0]]:\n",
+    "                distance[i[0]] = cost\n",
+    "                heapq.heappush(q, (cost, i[0]))\n",
+    "                \n",
+    "dijkstra(start)\n",
+    "\n",
+    "for i in range(1, n+1):\n",
+    "    if distance[i] == INF:\n",
+    "        print(\"INFINITY\")\n",
+    "    else:\n",
+    "        print(distance[i])"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "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": "3.10.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}