馬斯克:特斯拉超級充電網路的峰值充電功率將從 250kW 升級到 300kW
阿新 • • 發佈:2021-07-16
題目來源:104. 二叉樹的最大深度
給定一個二叉樹,找出其最大深度。
二叉樹的深度為根節點到最遠葉子節點的最長路徑上的節點數。
說明:葉子節點是指沒有子節點的節點。
示例:
給定二叉樹[3,9,20,null,null,15,7]
,
3 / \ 9 20 / \ 15 7
返回它的最大深度3 。
/** * Definition for a binary tree node. * function TreeNode(val, left, right) { * this.val = (val===undefined ? 0 : val) * this.left = (left===undefined ? null : left) * this.right = (right===undefined ? null : right) * }*/ /** * @param {TreeNode} root * @return {number} */ var maxDepth = function(root) { let h = 0 if(!root){ return h } let stack = [] stack.push([root]) while(stack.length){ let curLevel = stack.shift() let len = curLevel.length if(len>0){ h += 1 } let level= [] for(let i = 0;i<len;i++){ let node = curLevel[i] if(node.left){ level.push(node.left) } if(node.right){ level.push(node.right) } } if(level.length>0){ stack.push(level) } } return h };
Python3
# Definition for a binary tree node.# class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self.right = right class Solution: def maxDepth(self, root: TreeNode) -> int: res = 0 if not root: return res stack = list() stack.append([root]) while stack: curLevel = stack.pop(0) if curLevel: res += 1 level = list() for node in curLevel: if node.left: level.append(node.left) if node.right: level.append(node.right) if level: stack.append(level) return res