# LeetCode 1437. Check If All 1’s Are at Least Length K Places Away

## Description

https://leetcode.com/problems/check-if-all-1s-are-at-least-length-k-places-away/

Given an array `nums` of 0s and 1s and an integer `k`, return `True` if all 1’s are at least `k` places away from each other, otherwise return `False`.

Example 1:

```Input: nums = [1,0,0,0,1,0,0,1], k = 2
Output: true
Explanation: Each of the 1s are at least 2 places away from each other.
```

Example 2:

```Input: nums = [1,0,0,1,0,1], k = 2
Output: false
Explanation: The second 1 and third 1 are only one apart from each other.```

Example 3:

```Input: nums = [1,1,1,1,1], k = 0
Output: true
```

Example 4:

```Input: nums = [0,1,0,1], k = 1
Output: true
```

Constraints:

• `1 <= nums.length <= 105`
• `0 <= k <= nums.length`
• `nums[i]` is `0` or `1`

## Explanation

Find the distance between 1’s and check if all distance are at least k places away..

## Python Solution

``````class Solution:
def kLengthApart(self, nums: List[int], k: int) -> bool:

i = None
for j, num in enumerate(nums):
if num == 1:
if i != None and j - i <= k:
return False

i = j

return True``````
• Time Complexity: O(N).
• Space Complexity: O(1).