package JianZhiOffer54;

/**
 * @author ：dazhu
 * @date ：Created in 2020/4/9 11:30
 * @description：二叉搜索树的第k大节点
 * @modified By：
 * @version: $
 */
public class Main {
    public static void main(String[]args){
        TreeNode n1 = new TreeNode(1);
        TreeNode n2 = new TreeNode(2);
        TreeNode n3 = new TreeNode(3);
        TreeNode n4 = new TreeNode(4);
        TreeNode n5 = new TreeNode(5);
        TreeNode n6 = new TreeNode(6);

        n5.right = n6;
        n5.left = n3;
        n3.right = n4;
        n3.left = n2;
        n2.left = n1;

        Solution solution = new Solution();

        System.out.println(solution.kthLargest(n5,1));
    }
}


class Solution {
    private int largestNumber;
    //已经找到标志位，false没有找到，true已经找到
    private boolean flag = false;
    private int k ;
    public int kthLargest(TreeNode root, int k) {
        this.k = k;
        recur(root);
        return largestNumber;
    }

    public void recur(TreeNode node) {
        if(flag == true){
            return;
        }
        if(node == null){
            return;
        }
        //右边的中序遍历
        recur(node.right);
        if(k == 1&&flag ==false){
            //k == 1意味着已经遍历k-1次，当前位置就是目标位置
            largestNumber = node.val;
            flag = true;
            return;
        }
        k--;
        recur(node.left);
    }
}

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode(int x) { val = x; }
}