From: ltnwgl <ltnwgl@gmail.com>
Date: Fri, 24 Mar 2017 03:55:22 +0000 (+0800)
Subject: container/heap: optimization when selecting smaller child
X-Git-Tag: go1.9beta1~312
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=f5352a7763c8f96f7f092990d64339eae0623263;p=gostls13.git

container/heap: optimization when selecting smaller child

In down(), if two children are equal, we can choose either one.
Inspired by https://codereview.appspot.com/6613064/

Change-Id: Iaad4ca5e2f5111bf3abb87f606584e7d274c620b
Reviewed-on: https://go-review.googlesource.com/38612
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
---

diff --git a/src/container/heap/heap.go b/src/container/heap/heap.go
index 7110c513f0..af05261c10 100644
--- a/src/container/heap/heap.go
+++ b/src/container/heap/heap.go
@@ -107,7 +107,7 @@ func down(h Interface, i0, n int) bool {
 			break
 		}
 		j := j1 // left child
-		if j2 := j1 + 1; j2 < n && !h.Less(j1, j2) {
+		if j2 := j1 + 1; j2 < n && h.Less(j2, j1) {
 			j = j2 // = 2*i + 2  // right child
 		}
 		if !h.Less(j, i) {