leetcode-5.24[*671. 二叉樹中第二小的節點、728. 自除數、645. 錯誤的集合]（python實現)

題目1

題解1

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

class Solution:
    """
        每個節點都是正數，並且每個節點的子節點數量只能爲 2 或 0。如果一個節點有兩個子節點的話，那麼這個節點的值不大於它的子節點的值
    """
    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)

附上題目鏈接

題目2

題解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

附上題目鏈接

題目3

題解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()]

附上題目鏈接