题解 | #完全二叉树结点数#

/**
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
    int nodeNum(struct TreeNode* head) {
        if(head == nullptr){
            return 0;
        }
        
        int left_num = nodeNum(head->left);
        int right_num = nodeNum(head->right);
        
        return left_num+right_num+1;
        
    }
};