Leetcode 111 二叉树最小深度

class Solution:
    def minDepth(self, root: TreeNode) -> int:
        if not root:
            return 0
        if not root.left and not root.right:
            return 1
        min_depth = float('inf')
        if root.left:
            min_depth = min(self.minDepth(root.left), min_depth)
        if root.right:
            min_depth = min(self.minDepth(root.right), min_depth)
        return min_depth + 1

class Solution:
    def minDepth(self, root: TreeNode) -> int:
        if not root:
            return 0
        queue = []
        queue.append((root, 1))
        while queue:
            node, level = queue.pop(0)
            if not node.left and not node.right:
                return level
            if node.left:
                queue.append((node.left, level + 1))
            if node.right:
                queue.append((node.right, level + 1))
        return 0