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遍历有序二叉树,顺序输出每一层node 的data。
比如二叉树
6
3 9
1 5 7 10
打印输出就是,6,3,9,1,5,7,10。
这个利用队列实现非常高效。
package dayscode;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
/**
* 二叉树层次遍历打印输出
*/
public class BSTTraversal {
static class Node {
Node left, right;
int data;
Node(int data) {
this.data = data;
left = right = null;
}
}
public static Node insert(Node root, int data) {
if (root == null) {
return new Node(data);
}
Node cur;
if (data <= root.data) {
cur = insert(root.left, data);
root.left = cur;
}
else{
cur = insert(root.right, data);
root.right = cur;
}
return root;
}
static void levelOrder(Node root) {
Queue<Node> elements = new LinkedList();//利用队列先进先出
elements.offer(root);
while (!elements.isEmpty()) {//队列循环输出
Node tmp = elements.poll();
System.out.print(tmp.data + " ");
if (tmp.left != null) {
elements.offer(tmp.left);
}
if (tmp.right != null) {
elements.offer(tmp.right);
}
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int T = sc.nextInt();
Node root = null;
while (T-- > 0) {
int data = sc.nextInt();
root = insert(root, data);
}
levelOrder(root);
}
}