“SlidingWindowMaximum” error

[piglikeYoung]

https://github.com/soapyigu/LeetCode-Swift/blob/master/Array/SlidingWindowMaximum.swift

testcase: [ 2, 3, 4, 2, 6, 2, 5, 1 ]
expected: [4, 4, 6, 6, 6, 5]
errorResult: [4, 4, 6, 6, 5, 5]

Modify

func maxSlidingWindow(_ nums: [Int], _ k: Int) -> [Int] {
        guard k > 0 && k <= nums.count else {
            return []
        }

        var maxIdx = [Int]()
        var res = [Int]()

        for i in 0..<nums.count {
            while maxIdx.count > 0 && nums[maxIdx.last!] <= nums[i] {
                maxIdx.removeLast()
            }
            maxIdx.append(i)
            if i >= k - 1 {
                if maxIdx.first! + k == i {
                    maxIdx.removeFirst()
                }
                res.append(nums[maxIdx.first!])
            }
        }

        return res
    }