leetcode-5.24[*671. 二叉树中第二小的节点、728. 自除数、645. 错误的集合]（python实现)

题目1

题解1

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    """
        每个节点都是正数，并且每个节点的子节点数量只能为 2 或 0。如果一个节点有两个子节点的话，那么这个节点的值不大于它的子节点的值
    """
    def findSecondMinimumValue(self, root: TreeNode) -> int:
        return self.helper(root,root.val)

    def helper(self,root,value):
        if not root:
            return -1
        if root.val>value:
            return root.val
        l=self.helper(root.left,value)
        r=self.helper(root.right,value)
        if l==-1:
            return r
        if r==-1:
            return l
        return min(r,l)

附上题目链接

题目2

题解2

class Solution:
    def selfDividingNumbers(self, left: int, right: int) -> List[int]:
        res = []
        for num in range(left,right+1):
            temp = num
            while temp:
                if temp%10 == 0 or num % (temp%10) != 0:
                    break
                temp //= 10
            else:
                res.append(num)
        return res

附上题目链接

题目3

题解3

class Solution:
    def findErrorNums(self, nums: List[int]) -> List[int]:
        err = sum(nums) - sum(set(nums))
        res = set(range(1,len(nums) +1)) - set(nums)
        return [err,res.pop()]

附上题目链接