gods/examples/binaryheap.go

// Copyright (c) 2015, Emir Pasic. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package examples

import (
	"github.com/emirpasic/gods/trees/binaryheap"
	"github.com/emirpasic/gods/utils"
)

// BinaryHeapExample to demonstrate basic usage of BinaryHeap
func BinaryHeapExample() {

	// Min-heap
	heap := binaryheap.NewWithIntComparator() // empty (min-heap)
	heap.Push(2)                              // 2
	heap.Push(3)                              // 2, 3
	heap.Push(1)                              // 1, 3, 2
	heap.Values()                             // 1, 3, 2
	_, _ = heap.Peek()                        // 1,true
	_, _ = heap.Pop()                         // 1, true
	_, _ = heap.Pop()                         // 2, true
	_, _ = heap.Pop()                         // 3, true
	_, _ = heap.Pop()                         // nil, false (nothing to pop)
	heap.Push(1)                              // 1
	heap.Clear()                              // empty
	heap.Empty()                              // true
	heap.Size()                               // 0

	// Max-heap
	inverseIntComparator := func(a, b interface{}) int {
		return -utils.IntComparator(a, b)
	}
	heap = binaryheap.NewWith(inverseIntComparator) // empty (min-heap)
	heap.Push(2)                                    // 2
	heap.Push(3)                                    // 3, 2
	heap.Push(1)                                    // 3, 2, 1
	heap.Values()                                   // 3, 2, 1
}