Can Place Flowers

Problem Statement

You have a flowerbed (array of 0s and 1s, where 0 is empty and 1 is a flower) and want to plant n new flowers. Flowers can’t be planted adjacent to each other. Determine if you can plant all n flowers. This easy-level greedy problem is about spacing—can you fit them all?

Example

Input: flowerbed = [1,0,0,0,1], n = 1

Output: true (plant at index 2)

Input: flowerbed = [1,0,0,0,1], n = 2

Output: false (only one spot available)

Code

public class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        int count = 0;
        int i = 0;
        while (i < flowerbed.length) {
            if (flowerbed[i] == 0) {
                boolean left = (i == 0) || (flowerbed[i-1] == 0);
                boolean right = (i == flowerbed.length-1) || (flowerbed[i+1] == 0);
                if (left && right) {
                    flowerbed[i] = 1;
                    count++;
                    i++;
                }
            }
            i++;
        }
        return count >= n;
    }
}
            

def can_place_flowers(flowerbed, n):
    count = 0
    i = 0
    while i < len(flowerbed):
        if flowerbed[i] == 0:
            left = (i == 0) or (flowerbed[i-1] == 0)
            right = (i == len(flowerbed)-1) or (flowerbed[i+1] == 0)
            if left and right:
                flowerbed[i] = 1
                count += 1
                i += 1
        i += 1
    return count >= n
            

function canPlaceFlowers(flowerbed, n) {
    let count = 0;
    let i = 0;
    while (i < flowerbed.length) {
        if (flowerbed[i] === 0) {
            let left = (i === 0) || (flowerbed[i-1] === 0);
            let right = (i === flowerbed.length-1) || (flowerbed[i+1] === 0);
            if (left && right) {
                flowerbed[i] = 1;
                count++;
                i++;
            }
        }
        i++;
    }
    return count >= n;
}
            

Explanation

• Greedy Choice: Plant flowers whenever possible, checking adjacent plots.
• Flow: Skip planted spots, plant if both sides are empty.
• Example: [1,0,0,0,1] → plant at 2, count=1.

Note