Add Soulution.go for 0025.Reverse Nodes in k-Group

Author: Yeqi Tao

solution/0025.Reverse Nodes in k-Group/Solution.go

@@ -0,0 +1,59 @@
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
+ func reverseKGroup(head *ListNode, k int) *ListNode {
+	start := head
+	var h *ListNode = nil
+	var t *ListNode = nil
+	ok := false
+	if h, t, ok = revert(start, k); !ok {
+		return head
+	}
+	r := h
+	p := t
+	print(2, r)
+	for ok {
+		start = t.Next
+		h, t, ok = revert(start, k)
+		p.Next = h
+		p = t
+	}
+	return r
+}
+
+func revert(head *ListNode, k int) (h, t *ListNode, ok bool) {
+	c := head
+	if !check(c, k) {
+		return head, nil, false
+	}
+
+	t = head
+	var p *ListNode = nil
+	for k > 0 {
+		temp := head
+		head = head.Next
+		temp.Next = p
+		p = temp
+		k--
+	}
+	h = p
+	t.Next = head
+	ok = true
+	print(11, h)
+	return
+}
+
+func check(head *ListNode, k int) bool {
+	for k > 0 {
+		if head == nil {
+			return false
+		}
+		k--
+		head = head.Next
+	}
+	return true
+}