题解 | #二叉搜索树的第k个节点#
二叉搜索树的第k个节点
https://www.nowcoder.com/practice/57aa0bab91884a10b5136ca2c087f8ff
/** * 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 proot TreeNode类 * @param k int整型 * @return int整型 */ int KthNode(TreeNode* proot, int k) { // write code here if (proot==nullptr||k<1) return -1; vector<int> ans; queue<TreeNode*> q; q.push(proot); while(!q.empty()){ for(int n=q.size();n--;){ auto node =q.front(); q.pop(); ans.push_back(node->val); if(node->left) q.push(node->left); if(node->right) q.push(node->right); } } sort(ans.begin(),ans.end()); if(k>ans.size()) return -1; return ans[k-1]; } };