can-place-flowers.js

/**
 * Can Place Flowers
 *
 * Suppose you have a long flowerbed in which some of the plots are planted and some are not. However, flowers cannot
 * be planted in adjacent plots - they would compete for water and both would die.
 *
 * Given a flowerbed (represented as an array containing 0 and 1, where 0 means empty and 1 means not empty), and a
 * number n, return if n new flowers can be planted in it without violating the no-adjacent-flowers rule.
 *
 * Example 1:
 * Input: flowerbed = [1,0,0,0,1], n = 1
 * Output: True
 *
 * Example 2:
 * Input: flowerbed = [1,0,0,0,1], n = 2
 * Output: False
 *
 * Note:
 * - The input array won't violate no-adjacent-flowers rule.
 * - The input array size is in the range of [1, 20000].
 * - n is a non-negative integer which won't exceed the input array size.
 */

/**
 * @param {number[]} flowerbed
 * @param {number} n
 * @return {boolean}
 */
const canPlaceFlowers = (flowerbed, n) => {
  let count = 0;

  for (let i = 0; i < flowerbed.length && count < n; i++) {
    if (flowerbed[i] === 0) {
      // Get next and prev flower bed slot values.
      // If i lies at the ends the next and prev are considered as 0.
      const next = i === flowerbed.length - 1 ? 0 : flowerbed[i + 1];
      const prev = i === 0 ? 0 : flowerbed[i - 1];

      if (next === 0 && prev === 0) {
        flowerbed[i] = 1;
        count++;
      }
    }
  }

  return count === n;
};

export { canPlaceFlowers };