二叉樹:節點的個數
阿新 • • 發佈:2021-01-19
二叉樹:節點的個數
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int countNodes(TreeNode* root) {
if(root == NULL)
return 0;
int left = countNodes(root->left);
int right = countNodes(root->right);
return left + right + 1;
}
};