Last Updated on 2023-03-20 by Clay
題目
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 * 104flowerbed[i]is0or1.- There are no two adjacent flowers in
flowerbed. 0 <= n <= flowerbed.length
題目給定一個花壇的列表，0 代表並未種花、1 代表已經有種花。種花存在著限制，就是花不能相鄰地種植。
題目還會給定一個 n 值，代表著我們還希望能夠種多少朵花。如果能在當前的花壇中種完，回傳 true 反之則回傳 false。
解題思路
我們依序遍歷整個花壇的列表，並在左右兩側為 0 或超出邊界的情況種植花朵（也就是把列表當前位置補上 1），然後將 n 減去 1，繼續遍歷下一個數值，頗有 greedy search 的感覺。
如果 n 能夠減至 0，則代表可以完成種植任務。
C++ 範例程式碼
class Solution {
public:
bool canPlaceFlowers(vector<int>& flowerbed, int n) {
for (int i=0; i<flowerbed.size(); ++i) {
if ((flowerbed[i] == 0) && (i == 0 || flowerbed[i-1] == 0) && (i == flowerbed.size()-1 || flowerbed[i+1] == 0)) {
flowerbed[i] = 1;
--n;
}
if (n <= 0) {
return true;
}
}
return n <= 0;
}
};Python 範例程式碼
class Solution:
def canPlaceFlowers(self, flowerbed: List[int], n: int) -> bool:
for i in range(len(flowerbed)):
if flowerbed[i] == 0 and (i == 0 or flowerbed[i-1] == 0) and (i == len(flowerbed)-1 or flowerbed[i+1] == 0):
flowerbed[i] = 1
n -= 1
if n <= 0:
return True
return n <= 0