修改iterator ToHead ToTail的实现, 和使用方法.

priority_queuekey/iterator.go

@@ -31,13 +31,36 @@ func NewIteratorWithCap(n *Node, cap int) *Iterator {
 }
 
 func (iter *Iterator) ToHead() {
-	for iter.Prev() {
+	if iter.cur == nil {
+		iter.cur = iter.up
 	}
+
+	for iter.cur.parent != nil {
+		iter.cur = iter.cur.parent
+	}
+
+	for iter.cur.children[1] != nil {
+		iter.cur = iter.cur.children[1]
+	}
+	iter.SetNode(iter.cur)
+	iter.cur = nil
 }
 
 func (iter *Iterator) ToTail() {
-	for iter.Next() {
+
+	if iter.cur == nil {
+		iter.cur = iter.up
 	}
+
+	for iter.cur.parent != nil {
+		iter.cur = iter.cur.parent
+	}
+
+	for iter.cur.children[0] != nil {
+		iter.cur = iter.cur.children[0]
+	}
+	iter.SetNode(iter.cur)
+	iter.cur = nil
 }
 
 func (iter *Iterator) GetNode() *Node {

priority_queuekey/priority_queuekey_test.go

@@ -387,13 +387,15 @@ func TestPriorityQueue_Iterator(t *testing.T) {
 
 	values := pq.Values()
 	for i := 0; ; i++ {
-		if values[i] != iter.Value() {
-			t.Error(values[i], " != ", iter.Value())
-		}
 
 		if !iter.Next() {
 			break
 		}
+
+		if values[i] != iter.Value() {
+			t.Error(values[i], " != ", iter.Value())
+		}
+
 	}
 }
 
@@ -481,10 +483,10 @@ func TestMain(t *testing.T) {
 	log.Println(pq.String())
 	// log.Println(iter.Value()) 直接使用会报错,
 	iter.ToHead()
+	iter.Next()
 	log.Println(iter.Value())              // 起始最大值. true 5
 	log.Println(iter.Prev(), iter.Value()) // false 5
 
 	// Prev 大到小
 	log.Println(iter.Next(), iter.Value()) // true 4
-
 }