while tail and tail.next and count < k:
count += 1
tail = tail.next
if count != k:
break
node = head
next = node.next
for i in range(k-1):
tmp = next.next
next.next = node
node = next
next = tmp
if not prev:
newhead = tail
else:
prev.next = tail
prev = head
head.next = tmp
head = tmp
tail = head
if not newhead:
newhead = head
return newhead
a = ListNode.from_list([1,2,3,4,5,6])
s = Solution()
print(s.reverseKGroup(a, 2))
# @return a tree node
def sortedListToBST(self, head):
if not head:
return None
if not head.next:
node = TreeNode(head.val)
return node
fast = head
slow = head
prev = None
while fast.next and fast.next.next:
fast = fast.next.next
prev = slow
slow = slow.next
node = TreeNode(slow.val)
right = slow.next
if prev:
prev.next = None
node.left = self.sortedListToBST(head)
else:
node.left = self.sortedListToBST(None)
node.right = self.sortedListToBST(right)
return node
a = [1,2,3,4]
l = ListNode.from_list(a)
s = Solution()
print(s.sortedListToBST(l))
def rotateRight(self, head, k):
if not head or k <= 0:
return head
num = 0
node = head
while node:
node = node.next
num += 1
k = k % num
if k == 0:
return head
fast = head
for i in range(k):
fast = fast.next
slow = head
while fast.next:
slow = slow.next
fast = fast.next
fast.next = head
head = slow.next
slow.next = None
return head
node = ListNode.from_list([1])
s = Solution()
print(s.rotateRight(node, 1))
head = None
curr = None
while nodes:
n = len(nodes)
minv = float('inf')
index = 0
for i in range(n):
node = nodes[i]
if node.val < minv:
minv = node.val
index = i
if not head:
head = ListNode(minv)
curr = head
else:
curr.next = ListNode(minv)
curr = curr.next
node = nodes[index].next
if not node:
nodes.pop(index)
else:
nodes[index] = node
return head
a = ListNode.from_list([1,2,3])
b = ListNode.from_list([2,3,4])
s = Solution()
print(s.mergeKLists([a,b]))