(per suggestion by Doug McIlroy)
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/
50580046
// min-heap with the following invariants (established after
// Init has been called or if the data is empty or sorted):
//
-// !h.Less(j, i) for 0 <= i < h.Len() and j = 2*i+1 or 2*i+2 and j < h.Len()
+// !h.Less(j, i) for 0 <= i < h.Len() and 2*i+1 <= j <= 2*i+2 and j < h.Len()
//
// Note that Push and Pop in this interface are for package heap's
// implementation to call. To add and remove things from the heap,