题目：求整数次方
def power(base, exponent):
if equal_zero(base) and exponent < 0:
raise ZeroDivisionError
ret = power_value(base, abs(exponent))
if exponent < 0:
return 1.0 / ret
else:
return ret
def equal_zero(num):
if abs(num - 0.0) < 0.0000001:
return True
def power_value(base, exponent):
if exponent == 0:
return 1
if exponent == 1:
return base
ret = power_value(base, exponent >> 1)
ret *= ret
if exponent & 1 == 1:
ret *= base
return ret题目：O(1)时间删除链表结点
def delete_node(link, node):
if node == link: # 只有一个结点
del node
if node.next is None: # node是尾结点
while link:
if link.next == node:
link.next = None
link = link.next
else:
node.val = node.next.val
n_node = node.next
node.next = n_node.next
del n_node题目：调整数组，使奇数在偶数前
def reorder(nums, func):
left, right = 0, len(nums) - 1
while left < right:
while not func(nums[left]):
left += 1
while func(nums[right]):
right -= 1
if left < right:
nums[left], nums[right] = nums[right], nums[left]
def is_even(num):
return (num & 1) == 0题目：链表中倒数第k个结点
def last_kth(link, k):
if not link or k<=0:
return None
move = link
while move and k-1>=0:
move = move.next
k-=1
while move:
move = move.next
link = link.next
if k==0:
return link.val
return None题目：反转链表
def reverse_link(head):
if not head or not head.next:
return head
then = head.next
head.next = None
last = then.next
while then:
then.next = head
head = then
then = last
if then:
last = then.next
return head题目：合并两个排序的链表
def merge_link(head1, head2):
if not head1:
return head2
if not head2:
return head1
if head1.val <= head2.val:
ret = head1
ret.next = merge_link(head1.next, head2)
else:
ret = head2
ret.next = merge_link(head1, head2.next)
return ret题目：树的子结构
def sub_tree(tree1, tree2):
if tree1 and tree2:
if tree1.val == tree2.val:
return sub_tree(tree1.left, tree2.left) and sub_tree(tree1.right, tree2.right)
else:
return sub_tree(tree1.left, tree2) and sub_tree(tree1.right, tree2)
if not tree1 and tree2:
return False
return True