LeetCode235.二叉搜索树的最近公共祖先

题目

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        if((p->val - root->val) * (q->val - root->val)<0) return root;
        //if(root == p ) return p;
        //if(root == q) return q;
        if(p->val < root->val && q->val < root->val) return lowestCommonAncestor(root->left,p,q);
        if(p->val > root->val && q->val > root->val) return lowestCommonAncestor(root->right,p,q);
        return root;
    }
};

官方答案，学习

class Solution {
public:
    vector<TreeNode*> getPath(TreeNode* root,TreeNode* target){
        vector<TreeNode*>path;
        TreeNode* node = root;
        while(node!=target){
            path.push_back(node);
            if(target->val > node->val) node = node->right;
            else node = node->left;
        }
        path.push_back(node);
        return path;
    }
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        vector<TreeNode*>path_p = getPath(root,p);
        vector<TreeNode*>path_q = getPath(root,q);
        TreeNode* ancestor;
        for(int i = 0;i < path_p.size() && i < path_q.size();i++){
            if(path_p[i] == path_q[i]) ancestor = path_p[i];
            else break;
        }
        return ancestor;

    }
};