escape-the-ghosts.js

/**
 * Escape The Ghosts
 *
 * You are playing a simplified Pacman game. You start at the point (0, 0), and your destination is
 * (target[0], target[1]). There are several ghosts on the map, the i-th ghost starts at (ghosts[i][0],
 * ghosts[i][1]).
 *
 * Each turn, you and all ghosts simultaneously *may* move in one of 4 cardinal directions: north, east,
 * west, or south, going from the previous point to a new point 1 unit of distance away.
 *
 * You escape if and only if you can reach the target before any ghost reaches you (for any given moves
 * the ghosts may take.)  If you reach any square (including the target) at the same time as a ghost,
 * it doesn't count as an escape.
 *
 * Return True if and only if it is possible to escape.
 *
 * Example 1:
 *
 * Input:
 * ghosts = [[1, 0], [0, 3]]
 * target = [0, 1]
 *
 * Output: true
 *
 * Explanation:
 * You can directly reach the destination (0, 1) at time 1, while the ghosts located at (1, 0) or (0, 3)
 * have no way to catch up with you.
 *
 * Example 2:
 *
 * Input:
 * ghosts = [[1, 0]]
 * target = [2, 0]
 *
 * Output: false
 *
 * Explanation:
 * You need to reach the destination (2, 0), but the ghost at (1, 0) lies between you and the destination.
 *
 * Example 3:
 *
 * Input:
 * ghosts = [[2, 0]]
 * target = [1, 0]
 *
 * Output: false
 *
 * Explanation:
 * The ghost can reach the target at the same time as you.
 *
 * Note:
 *
 * - All points have coordinates with absolute value <= 10000.
 * - The number of ghosts will not exceed 100.
 */

/**
 * @param {number[][]} ghosts
 * @param {number[]} target
 * @return {boolean}
 */
const escapeGhosts = (ghosts, target) => {
  for (let ghost of ghosts) {
    if (distance(ghost, target) <= distance([0, 0], target)) {
      return false;
    }
  }
  return true;
};

const distance = (p1, p2) => {
  return Math.abs(p1[0] - p2[0]) + Math.abs(p1[1] - p2[1]);
};

export { escapeGhosts };