https://leetcode.com/problems/k-empty-slots/

https://leetcode.com/articles/k-empty-slots/

You have N bulbs in a row numbered from 1 to N. Initially, all the bulbs are turned off. We turn on exactly one bulb everyday until all bulbs are on after N days.

You are given an array bulbs of length N where bulbs[i] = x means that on the (i+1)th day, we will turn on the bulb at position x where i is 0-indexed and x is 1-indexed.

Given an integer K, find out the minimum day number such that there exists two turned on bulbs that have exactly K bulbs between them that are all turned off.

If there isnâ€™t such day, return -1.

Example 1:

Input:

bulbs: [1,3,2]

K: 1

Output: 2

Explanation:

On the first day: bulbs[0] = 1, first bulb is turned on: [1,0,0]

On the second day: bulbs[1] = 3, third bulb is turned on: [1,0,1]

On the third day: bulbs[2] = 2, second bulb is turned on: [1,1,1]

We return 2 because on the second day, there were two on bulbs with one off bulb between them.

Example 2:

Input:

bulbs: [1,2,3]

K: 1

Output: -1

Note:

1 <= N <= 20000

1 <= bulbs[i] <= N

bulbs is a permutation of numbers from 1 to N.

0 <= K <= 20000

1 | //O(N*LogN) |