container/heap: avoid up() invoke if down() success at heap.Remove()

Change-Id: I6c210e0c23ca533e1f303f88ef9dcb629a294a2a
Reviewed-on: https://go-review.googlesource.com/43472
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/container/heap/heap.go b/src/container/heap/heap.go
index af05261c10..b2c64276c8 100644
--- a/src/container/heap/heap.go
+++ b/src/container/heap/heap.go
@@ -72,8 +72,9 @@ func Remove(h Interface, i int) interface{} {
 	n := h.Len() - 1
 	if n != i {
 		h.Swap(i, n)
-		down(h, i, n)
-		up(h, i)
+		if !down(h, i, n) {
+			up(h, i)
+		}
 	}
 	return h.Pop()
 }