- Difficulty: Hard
- Tags: LeetCode, Hard, Greedy, Queue, Array, Binary Search, Prefix Sum, Sliding Window, leetcode-2528, O(nlogk), O(n)
Problem
You are given a 0-indexed integer array stations
of length n
, where stations[i]
represents the number of power stations in the ith
city.
Each power station can provide power to every city in a fixed range. In other words, if the range is denoted by r
, then a power station at city i
can provide power to all cities j
such that |i - j| <= r
and 0 <= i, j <= n - 1
.
- Note that
|x|
denotes absolute value. For example,|7 - 5| = 2
and|3 - 10| = 7
.
The power of a city is the total number of power stations it is being provided power from.
The government has sanctioned building k
more power stations, each of which can be built in any city, and have the same range as the pre-existing ones.
Given the two integers r
and k
, return the maximum possible minimum power of a city, if the additional power stations are built optimally.
Note that you can build the k
power stations in multiple cities.
Example 1:
Input: stations = [1,2,4,5,0], r = 1, k = 2 Output: 5 Explanation: One of the optimal ways is to install both the power stations at city 1. So stations will become [1,4,4,5,0]. - City 0 is provided by 1 + 4 = 5 power stations. - City 1 is provided by 1 + 4 + 4 = 9 power stations. - City 2 is provided by 4 + 4 + 5 = 13 power stations. - City 3 is provided by 5 + 4 = 9 power stations. - City 4 is provided by 5 + 0 = 5 power stations. So the minimum power of a city is 5. Since it is not possible to obtain a larger power, we return 5.
Example 2:
Input: stations = [4,4,4,4], r = 0, k = 3 Output: 4 Explanation: It can be proved that we cannot make the minimum power of a city greater than 4.
Constraints:
n == stations.length
1 <= n <= 105
0 <= stations[i] <= 105
0 <= r <= n - 1
0 <= k <= 109