LeetCode in Kotlin
1043. Partition Array for Maximum Sum
Medium
Given an integer array arr, partition the array into (contiguous) subarrays of length at most k. After partitioning, each subarray has their values changed to become the maximum value of that subarray.
Return the largest sum of the given array after partitioning. Test cases are generated so that the answer fits in a 32-bit integer.
Example 1:
Input: arr = [1,15,7,9,2,5,10], k = 3
Output: 84
Explanation: arr becomes [15,15,15,9,10,10,10]
Example 2:
Input: arr = [1,4,1,5,7,3,6,1,9,9,3], k = 4
Output: 83
Example 3:
Input: arr = [1], k = 1
Output: 1
Constraints:
1 <= arr.length <= 5000 <= arr[i] <= 1091 <= k <= arr.length
Solution
class Solution {
fun maxSumAfterPartitioning(arr: IntArray, k: Int): Int {
val n = arr.size
val dp = IntArray(n)
for (right in 0 until n) {
var localMax = arr[right]
for (left in right downTo (-1).coerceAtLeast(right - k) + 1) {
localMax = localMax.coerceAtLeast(arr[left])
if (left == 0) {
dp[right] = dp[right].coerceAtLeast((right + 1) * localMax)
} else {
dp[right] = dp[right].coerceAtLeast(dp[left - 1] + (right - left + 1) * localMax)
}
}
}
return dp[n - 1]
}
}