剑指 Offer 54. 二叉搜索树的第k大节点
class Solution { int res; int k; public int kthLargest(TreeNode root, int k) { this.k = k; dfs(root); return res; } private void dfs(TreeNode root) { if(root == null){ return; } dfs(root.right); if(k == 0) return; if(--k == 0) { res = root.val; return; } dfs(root.left); } }