118차 2번 문제풀이

Author: Eric

live11/test118/문제2/황장현.js

@@ -0,0 +1,94 @@
+class MinHeap {
+  constructor() {
+    this.heap = [];
+  }
+  push(value) {
+    this.heap.push(value);
+    this.bubbleUp();
+  }
+
+  pop() {
+    if (this.heap.length === 1) return this.heap.pop();
+    const min = this.heap[0];
+    this.heap[0] = this.heap.pop();
+    this.bubbleDown();
+    return min;
+  }
+
+  bubbleUp() {
+    let index = this.heap.length - 1;
+
+    while (index > 0) {
+      const parentIndex = Math.floor((index - 1) / 2);
+      if (this.heap[parentIndex] <= this.heap[index]) break;
+      [this.heap[parentIndex], this.heap[index]] = [
+        this.heap[index],
+        this.heap[parentIndex],
+      ];
+      index = parentIndex;
+    }
+  }
+
+  bubbleDown() {
+    let index = 0;
+    const length = this.heap.length;
+
+    while (true) {
+      const left = 2 * index + 1;
+      const right = 2 * index + 2;
+      let smallest = index;
+
+      if (left < length && this.heap[left] < this.heap[smallest]) {
+        smallest = left;
+      }
+
+      if (right < length && this.heap[right] < this.heap[smallest]) {
+        smallest = right;
+      }
+
+      if (smallest === index) break;
+
+      [this.heap[index], this.heap[smallest]] = [
+        this.heap[smallest],
+        this.heap[index],
+      ];
+
+      index = smallest;
+    }
+  }
+
+  least() {
+    return this.heap[0];
+  }
+
+  size() {
+    return this.heap.length;
+  }
+}
+
+const input = require('fs')
+  .readFileSync(process.platform === 'linux' ? '/dev/stdin' : './input.txt')
+  .toString()
+  .trim()
+  .split('\n')
+  .map(Number);
+
+function solution(input) {
+  const N = input[0];
+  const cards = input.slice(1).map(Number);
+  const minHeap = new MinHeap();
+  for (let i = 0; i < N; i++) {
+    minHeap.push(cards[i]);
+  }
+
+  let sum = 0;
+  while (minHeap.size() > 1) {
+    const a = minHeap.pop();
+    const b = minHeap.pop();
+    sum += a + b;
+    minHeap.push(a + b);
+  }
+  return sum;
+}
+
+console.log(solution(input));