Node.js) 백준 1374번: 강의실

https://www.acmicpc.net/problem/1374

1374번: 강의실

 

같은 문제

https://www.acmicpc.net/problem/19598

19598번: 최소 회의실 개수

https://www.acmicpc.net/problem/11000

11000번: 강의실 배정

 

 

const [N, ...arr] = require('fs')
	.readFileSync('./dev/stdin')
	.toString()
	.trim()
	.split('\n')
	.map((v) => v.split(' ').map(Number));

class MinHeap {
	constructor() {
		this.heap = [];
	}
	swap(a, b) {
		[this.heap[a], this.heap[b]] = [this.heap[b], this.heap[a]];
	}

	size() {
		return this.heap.length;
	}

	push(value) {
		this.heap.push(value);
		let current = this.heap.length - 1;
		let parent = Math.floor((current - 1) / 2);

		while (this.heap[parent] > value) {
			this.swap(parent, current);
			current = parent;
			parent = Math.floor((current - 1) / 2);
		}
	}

	pop() {
		const last = this.heap.length - 1;
		let current = 0;
		this.swap(current, last); // 0번이 루트노드
		const value = this.heap.pop();

		while (current < last) {
			let left = current * 2 + 1;
			let right = current * 2 + 2;

			if (left >= last) {
				break;
			} else if (right >= last) {
				if (this.heap[current] > this.heap[left]) {
					this.swap(current, left);
					current = left;
				} else {
					break;
				}
			} else {
				if (this.heap[left] < this.heap[current] || this.heap[right] < this.heap[current]) {
					let next = this.heap[left] < this.heap[right] ? left : right;
					this.swap(current, next);
					current = next;
				} else {
					break;
				}
			}
		}
		return value;
	}
}

const minHeap = new MinHeap();

const sorted = arr.sort((a, b) => {
	return a[1] - b[1];
});

for (let i = 0; i < sorted.length; i++) {
	const [_, s, t] = sorted[i];
	if (minHeap.size() == 0) {
		minHeap.push(t);
	} else {
		const head = minHeap.heap[0];
		if (s >= head) {
			minHeap.pop();
		}
		minHeap.push(t);
	}
}
console.log(minHeap.size());