题目：
给定一棵二叉搜索树，请找出其中的第k大的结点。
实现
public class Solution63 {
public static BinaryTreeNode
kthNode(BinaryTreeNode root,
int k){
if(root==
null || k<
1){
return null;
}
List<BinaryTreeNode> tree_list =
new LinkedList<>();
traversal(root,tree_list);
if(k>tree_list.size()){
return null;
}
BinaryTreeNode result = tree_list.
get(k-
1);
return result;
}
public static void traversal(BinaryTreeNode root,List<BinaryTreeNode> tree_list){
if(root==
null){
return;
}
traversal(root.left,tree_list);
tree_list.add(root);
traversal(root.right,tree_list);
}
public static void main(String[] args) {
BinaryTreeNode n1 =
new BinaryTreeNode(
5);
BinaryTreeNode n2 =
new BinaryTreeNode(
3);
BinaryTreeNode n3 =
new BinaryTreeNode(
7);
BinaryTreeNode n4 =
new BinaryTreeNode(
2);
BinaryTreeNode n5 =
new BinaryTreeNode(
4);
BinaryTreeNode n6 =
new BinaryTreeNode(
6);
BinaryTreeNode n7 =
new BinaryTreeNode(
8);
n1.left = n2;
n1.right = n3;
n2.left = n4;
n2.right = n5;
n3.left = n6;
n3.right = n7;
printTree(n1);
System.
out.println();
for (
int i =
0; i <=
10; i++) {
BinaryTreeNode result = kthNode(n1,i);
if(result!=
null){
System.
out.printf(
"%-3d", result.
value);
}
}
}
private static void printTree(BinaryTreeNode root) {
if (root !=
null) {
printTree(root.left);
System.
out.printf(
"%-3d", root.
value);
printTree(root.right);
}
}
}
