- 技术
- [剑指offer] JAVA版题解 面试题54
代码演示：
package swordfingeroffer
;
import java
.util
.ArrayList
;
import java
.util
.List
;
public class InterviewQuestion54 {
public TreeNode
kthNode(TreeNode root
, int k
) {
if (null
== root
|| k
<= 0) {
return null
;
}
List
<TreeNode> cache
= new ArrayList<>();
kthNodeHelper(root
, k
, cache
);
return k
<= cache
.size() ? cache
.get(k
- 1) : null
;
}
private void kthNodeHelper(TreeNode root
, int k
, List
<TreeNode> cache
) {
if (null
== root
) {
return;
}
kthNodeHelper(root
.left
, k
, cache
);
cache
.add(root
);
if (cache
.size() == k
) {
return;
}
kthNodeHelper(root
.right
, k
, cache
);
}
}
Processed:
0.024, SQL:
9
