Maximum Sum Subarray of Size K

MaximumSumSubarrayOfSizeK.kt

/*
Given an array of positive numbers and a positive number ‘k’, find the maximum sum of any contiguous subarray of size ‘k’.

Example 1:

Input: [2, 1, 5, 1, 3, 2], k=3
Output: 9
Explanation: Subarray with maximum sum is [5, 1, 3].
Example 2:

Input: [2, 3, 4, 1, 5], k=2
Output: 7
Explanation: Subarray with maximum sum is [3, 4].
 */
fun main() {
    println(findMaxSumSubArray(intArrayOf(2, 1, 5, 1, 3, 2),3))
    println(findMaxSumSubArray(intArrayOf(2, 3, 4, 1, 5),2))
}

fun findMaxSumSubArray(array:IntArray, k:Int ):Int{
    var sum = 0
    var end = 0
    var max = 0
    array.forEachIndexed { index, i ->
        sum += i
        if (index >= k-1){
            max = sum.coerceAtLeast(max)
            sum-= array[end]
            end++
        }
    }
    return max
}