Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Note: A leaf is a node with no children.
Example:
Given binary tree [3,9,20,null,null,15,7],
3 / \ 9 20 / \ 15 7
return its depth = 3.
Subject to the effect:
Given a binary tree, the binary tree computing depth
understanding:
The root node is empty, a depth of 0; left subtree root node is empty, a depth of 1.
Each layer of recursion depth +1.
Code C ++:
/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: int maxDepth(TreeNode* root) { if(root==NULL) return 0; if(root->left==NULL && root->right==NULL) return 1; int left = maxDepth(root->left); int right = maxDepth(root->right); return left>right?left+1:right+1; } };
operation result:
When executed with: 12 MS memory consumption: 19.3 MB