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| type Element struct {
num int
frequency int
}
// 定义一个最小堆
type MinHeap []Element
func (h MinHeap) Len() int { return len(h) }
func (h MinHeap) Less(i, j int) bool { return h[i].frequency < h[j].frequency }
func (h MinHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *MinHeap) Push(x interface{}) {
*h = append(*h, x.(Element))
}
func (h *MinHeap) Pop() interface{} {
old := *h
n := len(old)
x := old[n-1]
*h = old[:n-1]
return x
}
func topKFrequent(nums []int, k int) []int {
// 使用哈希表统计每个元素的频率
frequencyMap := make(map[int]int)
for _, num := range nums {
frequencyMap[num]++
}
// 使用最小堆来维护频率最高的前 k 个元素
h := &MinHeap{}
heap.Init(h)
for num, frequency := range frequencyMap {
heap.Push(h, Element{num, frequency})
if h.Len() > k {
heap.Pop(h)
}
}
// 提取最小堆中的元素，即前 k 高频元素
res := make([]int, k)
for i := k - 1; i >= 0; i-- {
res[i] = heap.Pop(h).(Element).num
}
return res
}
|