/*
 * Copyright 2016-2018 Dgraph Labs, Inc.
 *
 * This file is available under the Apache License, Version 2.0,
 * with the Commons Clause restriction.
 */

package algo

type elem struct {
	val     uint64 // Value of this element.
	listIdx int    // Which list this element comes from.
}

type uint64Heap []elem

func (h uint64Heap) Len() int           { return len(h) }
func (h uint64Heap) Less(i, j int) bool { return h[i].val < h[j].val }
func (h uint64Heap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
func (h *uint64Heap) Push(x interface{}) {
	*h = append(*h, x.(elem))
}

func (h *uint64Heap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}