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// @Title: 滑动窗口的最大值 (滑动窗口的最大值 LCOF)
// @Author: 15816537946@163.com
// @Date: 2022-03-01 20:36:54
// @Runtime: 20 ms
// @Memory: 6.9 MB
// 优先队列（小根堆）
var a []int

type hp struct{ sort.IntSlice }

func (h *hp) Less(i, j int) bool {
	return a[h.IntSlice[i]] > a[h.IntSlice[j]]
}
func (h *hp) Push(v interface{}) {
	h.IntSlice = append(h.IntSlice, v.(int))
}
func (h *hp) Pop() interface{} {
	a := h.IntSlice
	v := a[len(a)-1]
	h.IntSlice = a[:len(a)-1]
	return v
}

func maxSlidingWindow(nums []int, k int) []int {
    if len(nums) ==0 || k == 0 {
        return nil 
    }
	a = nums
	q := &hp{make([]int, k)}
	for i := 0; i < k; i++ {
		q.IntSlice[i] = i
	}
	heap.Init(q)

	// nums 从小到大排列，大根堆
	n := len(nums)
	ans := make([]int, 1, n-k+1)
	ans[0] = nums[q.IntSlice[0]]

	for i := k; i < n; i++ {
		heap.Push(q, i)
		for q.IntSlice[0] <= i-k {
			heap.Pop(q)
		}
		ans = append(ans, nums[q.IntSlice[0]])
	}
	return ans

}

/*
    n := len(nums)
    ans := make([]int, 1, n-k+1)
    ans[0] = nums[q.IntSlice[0]]
    for i := k; i < n; i++ {
        heap.Push(q, i)
        for q.IntSlice[0] <= i-k {
            heap.Pop(q)
        }
        ans = append(ans, nums[q.IntSlice[0]])
    }
    return ans
}

*/