力扣222 代码随想录Day15 第四题

完全二叉树结点的数量

class Solution {
public:
    int countNodes(TreeNode* root) {
        if(root==NULL) return 0;
        TreeNode* le=root->left;
        TreeNode* ri=root->right;
        int ld=0;
        int rd=0;
        while(le){
            le=le->left;
            ld++;
        }
        while(ri){
            ri=ri->right;
            rd++;
        }
        if(ld==rd) return(2<<ld)-1;
        int ln=countNodes(root->left);
        int rn=countNodes(root->right);
        int result=ln+rn+1;
        return result;
    }
};