package main

func ShortestSubarray(nums []int, k int) int {
	if len(nums) == 0 {
		return -1
	}

	wndSz := 1
	wndStart := 0

	wndEnd := 0
	wndSum := 0

	wndPrevInitialSum := 0
	lenNums := len(nums)

	for wndSz = 1; wndSz <= lenNums; wndSz++ {

		wndSum = wndPrevInitialSum + nums[wndSz-1]
		wndPrevInitialSum = wndSum
		if wndSum >= k {
			return wndSz
		}

		for wndStart = 1; (wndStart + wndSz - 1) < lenNums; wndStart++ {

			wndEnd = wndStart + wndSz - 1
			wndSum = wndSum - nums[wndStart-1] + nums[wndEnd]

			if wndSum >= k {
				return wndSz
			}
		}
	}

	return -1
}