题解 | #二叉搜索树的最近公共祖先#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @param p int整型 
     * @param q int整型 
     * @return int整型
     */
    map<int,int> fu;
    void Find_fother(TreeNode* root,int f)
    {
        if(root==nullptr)
            return;
        fu[root->val]=f;
        Find_fother(root->left, root->val);
        Find_fother(root->right, root->val);
    }
    int lowestCommonAncestor(TreeNode* root, int p, int q) {
        Find_fother(root, -1);
        vector<int> num1,num2;
        num1.push_back(p);
        num2.push_back(q);
        while(fu[p]!=-1)
        {
            num1.push_back(fu[p]);
            p=fu[p];
        }
        while(fu[q]!=-1)
        {
            num2.push_back(fu[q]);
            q=fu[q];
        }
        for(int i=0;i<num1.size();i++)
            for(int j=0;j<num2.size();j++)
                if(num1[i]==num2[j])
                    return num1[i];
        return 0;
    }
};