LeetCode Minimum Depth of Binary Tree

LeetCode Minimum Depth of Binary Tree
LeetCode-solving-Minimum Depth of Binary Tree

Original question

Calculate the minimum height of a binary tree, that is, the number of nodes passing through the path from the root node to the nearest leaf node.

Note:

None

Example:

Input:

    3   / \  9  20    /  \   15   7  / 14

Output: 2

Solutions

You can achieve this through Tree breadth-first Traversal of Binary Tree Level Order Traversal. In the process of breadth-first Traversal, the height of each layer is increased by one. If a node is a leaf node, the current height is the minimum height.

AC Source Code

# Definition for a binary tree node.class TreeNode(object):    def __init__(self, x):        self.val = x        self.left = None        self.right = Noneclass Solution(object):    def minDepth(self, root):        """        :type root: TreeNode        :rtype: int        """        if root is None:            return 0        depth, curr_level = 0, [root]        while curr_level:            depth += 1            next_level = []            for n in curr_level:                left, right = n.left, n.right                if left is None and right is None:                    return depth                if left:                    next_level.append(left)                if right:                    next_level.append(right)            curr_level = next_level        return depthif __name__ == "__main__":    None