while l1 < l2:
zero = ll.ListNode(0)
zero.next = head1
head1 = zero
l1 += 1
#print "%d,%d" % (l1,l2)
ll.print_list(head1)
ll.print_list(head2)
res,flag = rec(head1,head2,l1-1)
if flag == 1:
return res+10**l1
else:
return res
def rec(head1,head2,i):
if i == 0:
tmp = head1.val+head2.val
return (tmp%10,tmp/10)
res = 0
tmp = head1.val + head2.val
head1 = head1.next
head2 = head2.next
other,flag = rec(head1,head2,i-1)
return ((tmp+flag)%10*(10**i)+other,tmp/10)
head1 = ll.create_list([1,2,1,7,1,6])
head2 = ll.create_list([5,9,2])
ll.print_list(head1)
ll.print_list(head2)
print add2(head1,head2)
import mylist as ll
import pdb
# check if a list is a palidrome
# O(n2) solution
def isPalidrome(head):
if not head or not head.next:
return True
size = ll.get_length(head)
return rec(head,size-1)
def rec(head,size):
if size < 1:
return True
a = head
i = 0
for i in range(size):
a = a.next
return head.val == a.val and rec(head.next,size-2)
head1 = ll.create_list([1,2,2])
#head2 = ll.create_list([5,9,2])
ll.print_list(head1)
#ll.print_list(head2)
print isPalidrome(head1)
import mylist as ll
# find the kth element in the list
def return_kth(head, k):
size = ll.get_length(head)
if not head or k > size:
print "invalid input"
return 0
# far = size-k+1
start = head
end = head
for i in range(k):
end = end.next
while end:
start = start.next
end = end.next
return start.val
head = ll.create_list([1, 2, 3, 4, 5])
ll.print_list(head)
print return_kth(head, 2)
