from utils import ListNode
class Solution(object):
def swapPairs(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
tmp_head = ListNode(0)
tmp_head.next = head
tmp = tmp_head
while tmp.next and tmp.next.next:
a, b = tmp.next, tmp.next.next
tmp.next, a.next = b, b.next
b.next = a
tmp = tmp.next.next
return tmp_head.next
if __name__ == '__main__':
s = Solution()
input_l = ListNode.create([1, 2, 3, 4])
print(input_l)
print(s.swapPairs(input_l))
o = r = ListNode(0)
while l1 and l2:
if l1.val < l2.val:
r.next = ListNode(l1.val)
l1 = l1.next
else:
r.next = ListNode(l2.val)
l2 = l2.next
r = r.next
if l1:
r.next = l1
else:
r.next = l2
return o.next
def mergeTwoLists2(self, l1, l2):
if l1 and l2:
if l1.val > l2.val: l1, l2 = l2, l1
l1.next = self.mergeTwoLists(l1.next, l2)
return l1 or l2
if __name__ == '__main__':
s = Solution()
input_l1 = ListNode.create([1, 2, 4])
input_l2 = ListNode.create([1, 3, 4])
print(input_l1)
print(input_l2)
print(s.mergeTwoLists(input_l1, input_l2))
print(s.mergeTwoLists2(input_l1, input_l2))
"""
def mergeTwoLists(l1, l2):
if l1 and l2:
if l1.val > l2.val: l1, l2 = l2, l1
l1.next = mergeTwoLists(l1.next, l2)
return l1 or l2
amount = len(lists)
new_lists = []
while amount > 1:
for i in range(0, amount // 2):
new_lists.append(mergeTwoLists(lists[i * 2], lists[i * 2 + 1]))
if amount % 2:
new_lists.append(lists[-1])
lists = new_lists
new_lists = []
amount = len(lists)
return lists[0] if amount > 0 else None
if __name__ == '__main__':
s = Solution()
input_l1 = ListNode.create([1, 4, 5])
input_l2 = ListNode.create([1, 3, 4])
input_l3 = ListNode.create([2, 6])
print(input_l1)
print(input_l2)
print(input_l3)
print(s.mergeKLists([input_l1, input_l2, input_l3]))
print(s.mergeKLists2([input_l1, input_l2, input_l3]))
