Node.js) 백준 29753번: 최소 성적

https://www.acmicpc.net/problem/29753

29753번: 최소 성적

const input = require('fs')
	.readFileSync('./dev/stdin')
	.toString()
	.trim()
	.split('\n')
	.map((v) => v.trim().split(' '));

const [N, X] = input.shift().map(Number);
const score = {
	'A+': 4.5,
	A0: 4.0,
	'B+': 3.5,
	B0: 3.0,
	'C+': 2.5,
	C0: 2.0,
	'D+': 1.5,
	D0: 1.0,
	F: 0.0,
};
const total = input.reduce((r, v) => {
	r += +v[0];
	return r;
}, 0);

const now = +input.pop()[0];

const sum = input.reduce((r, v) => {
	r += +score[v[1]] * +v[0];
	return r;
}, 0);

const possible = Object.entries(score).sort((a, b) => +a[1] - b[1]);

let answer;
for (let i = 0; i < possible.length; i++) {
	if (+((sum + now * possible[i][1]) / total).toFixed(3).slice(0, 4) > X) {
		answer = possible[i][0];
		break;
	}
}

console.log(answer ? answer : 'impossible');