Heap

What will be printed when the code below is executed?

package main
import (
    "container/heap"
    "fmt"
)
type IntHeap []int
func (h IntHeap) Len() int           { return len(h) }
func (h IntHeap) Less(i, j int) bool { return h[i] < h[j] }
func (h IntHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
func (h *IntHeap) Push(x interface{}) {
    *h = append(*h, x.(int))
}
func (h *IntHeap) Pop() interface{} {
    old := *h
    n := len(old)
    x := old[n-1]
    *h = old[0 : n-1]
    return x
}
func main() {
    h := &IntHeap{2, 1, 5}
    heap.Init(h)
    for h.Len() > 0 {
        fmt.Printf("%d ", heap.Pop(h))
    }
}

Answer

1 2 5