题目：

---

代码(首刷看解析 10.1）：

class Solution {
public:TreeNode* ans=nullptr;bool FindSon(TreeNode* root,TreeNode* p,TreeNode* q){if(root == nullptr)  return false;bool lson = FindSon(root->left,p,q);bool rson = FindSon(root->right,p,q);if( (lson&&rson) || ((root->val==p->val)||(root->val==q->val)) && (lson||rson) ){ans=root;}return  lson||rson||((root->val==p->val)||(root->val==q->val));}TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {FindSon(root,p,q);return ans;}
};

        后续多做几遍