LeetCode in Kotlin
1954. Minimum Garden Perimeter to Collect Enough Apples
Medium
In a garden represented as an infinite 2D grid, there is an apple tree planted at every integer coordinate. The apple tree planted at an integer coordinate (i, j) has |i| + |j| apples growing on it.
You will buy an axis-aligned square plot of land that is centered at (0, 0).
Given an integer neededApples, return the minimum perimeter of a plot such that at least neededApples apples are inside or on the perimeter of that plot.
The value of |x| is defined as:
xifx >= 0-xifx < 0
Example 1:
Input: neededApples = 1
Output: 8
Explanation: A square plot of side length 1 does not contain any apples. However, a square plot of side length 2 has 12 apples inside (as depicted in the image above). The perimeter is 2 * 4 = 8.
Example 2:
Input: neededApples = 13
Output: 16
Example 3:
Input: neededApples = 1000000000
Output: 5040
Constraints:
1 <= neededApples <= 1015
Solution
class Solution {
fun minimumPerimeter(neededApples: Long): Long {
var l: Long = 1
var r: Long = 1000000
var res = l
while (l <= r) {
val m = l + (r - l) / 2
val isPossible = check(m, neededApples)
if (isPossible) {
res = m
r = m - 1
} else {
l = m + 1
}
}
return res * 8
}
private fun check(len: Long, neededApples: Long): Boolean {
val sum = len * (len + 1) / 2
val applesPerQuadrant = 2 * len * sum
val totalCount = 4 * sum + 4 * applesPerQuadrant
return totalCount >= neededApples
}
}