LeetCode in Kotlin
2208. Minimum Operations to Halve Array Sum
Medium
You are given an array nums of positive integers. In one operation, you can choose any number from nums and reduce it to exactly half the number. (Note that you may choose this reduced number in future operations.)
Return the minimum number of operations to reduce the sum of nums by at least half.
Example 1:
Input: nums = [5,19,8,1]
Output: 3
Explanation: The initial sum of nums is equal to 5 + 19 + 8 + 1 = 33.
The following is one of the ways to reduce the sum by at least half:
Pick the number 19 and reduce it to 9.5.
Pick the number 9.5 and reduce it to 4.75.
Pick the number 8 and reduce it to 4.
The final array is [5, 4.75, 4, 1] with a total sum of 5 + 4.75 + 4 + 1 = 14.75.
The sum of nums has been reduced by 33 - 14.75 = 18.25, which is at least half of the initial sum, 18.25 >= 33/2 = 16.5.
Overall, 3 operations were used so we return 3.
It can be shown that we cannot reduce the sum by at least half in less than 3 operations.
Example 2:
Input: nums = [3,8,20]
Output: 3
Explanation: The initial sum of nums is equal to 3 + 8 + 20 = 31.
The following is one of the ways to reduce the sum by at least half:
Pick the number 20 and reduce it to 10.
Pick the number 10 and reduce it to 5.
Pick the number 3 and reduce it to 1.5.
The final array is [1.5, 8, 5] with a total sum of 1.5 + 8 + 5 = 14.5.
The sum of nums has been reduced by 31 - 14.5 = 16.5, which is at least half of the initial sum, 16.5 >= 31/2 = 16.5.
Overall, 3 operations were used so we return 3.
It can be shown that we cannot reduce the sum by at least half in less than 3 operations.
Constraints:
1 <= nums.length <= 1051 <= nums[i] <= 107
Solution
import java.util.Collections
import java.util.PriorityQueue
class Solution {
fun halveArray(nums: IntArray): Int {
val queue = PriorityQueue(nums.size, Collections.reverseOrder<Double>())
var sum = 0.0
var count = 0
for (num in nums) {
queue.add(num.toDouble())
sum += num
}
var hsum = sum
while (hsum > sum / 2) {
var maxElement = queue.poll()
maxElement /= 2
count++
hsum -= maxElement
queue.add(maxElement)
}
return count
}
}