update:25

Author: itcuihao

Diff for: problems/0025.reverse-nodes-in-k-group/run.go

@@ -1,6 +1,8 @@
 package pairs
 
-import "github.com/itcuihao/leetcode-go/structure"
+import (
+	"github.com/itcuihao/leetcode-go/structure"
+)
 
 //import "leetcode-go/structure"
 
@@ -40,3 +42,27 @@ func reverseKGroup(head *structure.ListNode, k int) *structure.ListNode {
 	}
 	return head
 }
+
+func reverseKGroup2(head *structure.ListNode, k int) *structure.ListNode {
+	node := head
+	for i := 0; i < k; i++ {
+		if node == nil {
+			return head
+		}
+		node = node.Next
+	}
+	newHead := reverse(head, node)
+	head.Next = reverseKGroup2(node, k)
+	return newHead
+}
+
+func reverse(first *structure.ListNode, last *structure.ListNode) *structure.ListNode {
+	prev := last
+	for first != last {
+		tmp := first.Next
+		first.Next = prev
+		prev = first
+		first = tmp
+	}
+	return prev
+}

Diff for: problems/0025.reverse-nodes-in-k-group/run_test.go

@@ -5,23 +5,40 @@ import (
 	"testing"
 )
 
-func TestRun(t *testing.T) {
-	var ls *structure.ListNode
-	ls = &structure.ListNode{
-		Val: 1,
+var ls = &structure.ListNode{
+	Val: 1,
+	Next: &structure.ListNode{
+		Val: 2,
 		Next: &structure.ListNode{
-			Val: 2,
+			Val: 3,
 			Next: &structure.ListNode{
-				Val: 3,
+				Val: 4,
 				Next: &structure.ListNode{
-					Val: 4,
-					Next: &structure.ListNode{
-						Val: 5,
-					},
+					Val: 5,
 				},
 			},
 		},
-	}
+	},
+}
 
-	reverseKGroup(ls, 2)
+func TestRun(t *testing.T) {
+	l := reverseKGroup(ls, 2)
+	l.Print()
+}
+
+func TestRun2(t *testing.T) {
+	l := reverseKGroup2(ls, 2)
+	l.Print()
+}
+
+func TestReverse(t *testing.T) {
+	node := ls
+	k := 3
+	for i := 0; i < k; i++ {
+		if node != nil {
+			node = node.Next
+		}
+	}
+	l := reverse(ls, node)
+	l.Print()
 }