106차 1번 문제풀이

Author: jinoo0306

live10/test106/문제2/조진우.js

@@ -0,0 +1,98 @@
+const input = require("fs")
+  .readFileSync(
+    process.platform === "linux"
+      ? "/dev/stdin"
+      : require("path").join(__dirname, "input.txt"),
+    "utf8"
+  )
+  .toString()
+  .trim()
+  .split("\n");
+
+function solution(input) {
+  const [n, m] = input[0].split(" ").map(Number);
+  const map = Array.from({ length: n + 1 }, () => []);
+
+  for (let i = 1; i <= m; i++) {
+    const [a, b, cost] = input[i].split(" ").map(Number);
+    map[a].push([b, cost]);
+    map[b].push([a, cost]);
+  }
+
+  const distance = Array(n + 1).fill(Infinity);
+  distance[1] = 0;
+
+  const heap = new MinHeap();
+  heap.push([0, 1]);
+
+  while (!heap.isEmpty()) {
+    const [curCost, curNode] = heap.pop();
+
+    if (distance[curNode] < curCost) continue;
+
+    for (let [next, nextCost] of map[curNode]) {
+      const newCost = curCost + nextCost;
+      if (newCost < distance[next]) {
+        distance[next] = newCost;
+        heap.push([newCost, next]);
+      }
+    }
+  }
+
+  return distance[n];
+}
+
+class MinHeap {
+  constructor() {
+    this.heap = [];
+  }
+
+  push(value) {
+    this.heap.push(value);
+    let i = this.heap.length - 1;
+    while (i > 0) {
+      const parent = Math.floor((i - 1) / 2);
+      if (this.heap[parent][0] <= this.heap[i][0]) break;
+      [this.heap[parent], this.heap[i]] = [this.heap[i], this.heap[parent]];
+      i = parent;
+    }
+  }
+
+  pop() {
+    if (this.heap.length === 1) return this.heap.pop();
+    const top = this.heap[0];
+    this.heap[0] = this.heap.pop();
+
+    let i = 0;
+    while (true) {
+      let left = i * 2 + 1;
+      let right = i * 2 + 2;
+      let smallest = i;
+
+      if (
+        left < this.heap.length &&
+        this.heap[left][0] < this.heap[smallest][0]
+      ) {
+        smallest = left;
+      }
+      if (
+        right < this.heap.length &&
+        this.heap[right][0] < this.heap[smallest][0]
+      ) {
+        smallest = right;
+      }
+      if (smallest === i) break;
+
+      [this.heap[i], this.heap[smallest]] = [this.heap[smallest], this.heap[i]];
+      i = smallest;
+    }
+
+    return top;
+  }
+
+  isEmpty() {
+    return this.heap.length === 0;
+  }
+}
+
+console.log(solution(input));