leetcode236+×î½ü¹«¹²×æÏÈ

https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) { //»­¸ö¶þ²æÊ÷Ä£ÄâÒ»ÏÂ
        if(!root||root==p||root==q) return root;
        TreeNode* left=lowestCommonAncestor(root->left, p, q);
        TreeNode* right=lowestCommonAncestor(root->right, p, q);
        if(left&&right) return root;
        if(!left) return right;
        return left; //!right
    }
};