1437.check-if-all-1-s-are-at-least-length-k-places-away.cpp

/*
 * @lc app=leetcode id=1437 lang=cpp
 *
 * [1437] Check If All 1's Are at Least Length K Places Away
 *
 * https://leetcode.com/problems/check-if-all-1s-are-at-least-length-k-places-away/description/
 *
 * algorithms
 * Medium (61.78%)
 * Likes:    242
 * Dislikes: 175
 * Total Accepted:    43.9K
 * Total Submissions: 70K
 * Testcase Example:  '[1,0,0,0,1,0,0,1]\n2'
 *
 * 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 <= 10^5
 * 0 <= k <= nums.length
 * nums[i] is 0 or 1
 * 
 * 
 */

// @lc code=start
class Solution {
public:
    bool kLengthApart(vector<int>& nums, int k) {
        for (int i = 0, first = -nums.size() - 1; i < nums.size(); ++i) {
            if (nums[i] == 1) {
                if (i - first - 1 < k)
                    return false;
                first = i;
            }            
        }
        return true;
    }
};
// @lc code=end