1921-eliminate-maximum-number-of-monsters.js

/**
 * 1921. Eliminate Maximum Number of Monsters
 * https://leetcode.com/problems/eliminate-maximum-number-of-monsters/
 * Difficulty: Medium
 *
 * You are playing a video game where you are defending your city from a group of n monsters. You
 * are given a 0-indexed integer array dist of size n, where dist[i] is the initial distance in
 * kilometers of the ith monster from the city.
 *
 * The monsters walk toward the city at a constant speed. The speed of each monster is given to
 * you in an integer array speed of size n, where speed[i] is the speed of the ith monster in
 * kilometers per minute.
 *
 * You have a weapon that, once fully charged, can eliminate a single monster. However, the weapon
 * takes one minute to charge. The weapon is fully charged at the very start.
 *
 * You lose when any monster reaches your city. If a monster reaches the city at the exact moment
 * the weapon is fully charged, it counts as a loss, and the game ends before you can use your
 * weapon.
 *
 * Return the maximum number of monsters that you can eliminate before you lose, or n if you can
 * eliminate all the monsters before they reach the city.
 */

/**
 * @param {number[]} dist
 * @param {number[]} speed
 * @return {number}
 */
var eliminateMaximum = function(dist, speed) {
  const n = dist.length;
  const arrivalTimes = new Array(n);

  for (let i = 0; i < n; i++) {
    arrivalTimes[i] = dist[i] / speed[i];
  }

  arrivalTimes.sort((a, b) => a - b);

  for (let i = 0; i < n; i++) {
    if (arrivalTimes[i] <= i) {
      return i;
    }
  }

  return n;
};