0605--can-place-flowers.txt

// https://leetcode.com/problems/can-place-flowers/description/
// 605. Can Place Flowers
// Easy
// 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.
// Given an integer array flowerbed containing 0's and 1's, where 0 means empty and 1 means not empty, and an integer n, return if n new flowers can be planted in the flowerbed 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
//
// Constraints:
// 1 <= flowerbed.length <= 2 * 104
// flowerbed[i] is 0 or 1.
// There are no two adjacent flowers in flowerbed.
// 0 <= n <= flowerbed.length


// .JS

/**
 * @param {number[]} flowerbed
 * @param {number} n
 * @return {boolean}
 */
var canPlaceFlowers = function (flowerbed, n) {
    let count = 0;
    for (let i = 0; i < flowerbed.length; i++) {
        if (flowerbed[i] === 0 &&
            (i === 0 || flowerbed[i - 1] === 0) &&
            (i === flowerbed.length - 1 || flowerbed[i + 1] === 0)
        ) {
            flowerbed[i] = 1;
            count++;
        }
        if (count >= n) return true;
    }
    return count >= n;
}

// -- OR --

/**
 * @param {number[]} flowerbed
 * @param {number} n
 * @return {boolean}
 */
var canPlaceFlowers = function (flowerbed, n) {
    for (let i = 0; i < flowerbed.length; i++) {
        if (flowerbed[i] === 0 &&
            (i === 0 || flowerbed[i - 1] === 0) &&
            (i === flowerbed.length - 1 || flowerbed[i + 1] === 0)
        ) {
            flowerbed[i] = 1;
            n--;
            i++;
        }
      if (n <= 0) return true;
    }
    return false;
}

// -- OR --

var canPlaceFlowers_______3 = function(flowerbed, n) {
    let current = 0; const size = flowerbed.length;
    for(var i = 0; i <= size; i++) {
        if (i < size && flowerbed[i] == 0) {
            current++;
            if (i == 0) current++;
            if (i == size - 1) current++;
        } else {
            n -= Math.trunc((current - 1) / 2);
            if (n <= 0) return true;
            current = 0;
        }
    }
    return false;
};

// PHP

class Solution
{
    /**
     * @param Integer[] $flowerbed
     * @param Integer $n
     * @return Boolean
     */
    function canPlaceFlowers(array $flowerbed, int $n): bool
    {
        for ($i = 0; $i < count($flowerbed); $i++) {
            if ($flowerbed[$i] == 0 &&
                ($i == 0 || $flowerbed[$i - 1] == 0) &&
                ($i == count($flowerbed) - 1 || $flowerbed[$i + 1] == 0)
            ) {
                $n--;
                $flowerbed[$i] = 1;
                $i++;
            }
            if ($n <= 0) {
                return true;
            }
        }
        return false;
    }
}

-- OR --
class Solution
{
    /**
     *  SOLUTION 2 - without modifying the input array
     * @param Integer[] $flowerbed
     * @param Integer $n
     * @return Boolean
     */
    function canPlaceFlowers($flowerbed, $n)
    {
        $count = 0;
        $flowerbedLength = count($flowerbed);
        for ($i = 0; $i <= $flowerbedLength; $i++) {
            if ($flowerbed[$i] == 0 &&
                $i < $flowerbedLength) {
                $count++;
                if ($i == 0) $count++;
                if ($i == $flowerbedLength - 1) $count++;
            } else {
                $n -= intdiv($count - 1, 2);
                if ($n <= 0) return true;
                $count = 0;
            }
        }
        return false;
    }
}

// C++
class Solution {
public:
    bool canPlaceFlowers(vector<int>& flowerbed, int n) {
        flowerbed.insert(flowerbed.begin(),0);
        flowerbed.push_back(0);
        for(int i = 1; i < flowerbed.size()-1; ++i)
        {
            if(flowerbed[i-1] + flowerbed[i] + flowerbed[i+1] == 0)
            {
                --n;
                ++i;
            }
        }
        return n <=0;
    }
};