import java.util.LinkedList;
import java.util.Queue;
public class Main {
class BinaryNode {
int val;
BinaryNode left;
BinaryNode right;
public BinaryNode(int val) {
this.val = val;
}
}//BinaryNode
private BinaryNode root;//根节点,这个属性很重要
public void printTreeLineByLine(BinaryNode root) {
Queue<BinaryNode> queue = new LinkedList<BinaryNode>();//把待打印的结点放在队列中
BinaryNode curNode;
queue.offer(root);
int curNum = 1;//当前行未打印的节点数
int next = 0;//下一行待打印的节点数
while (!queue.isEmpty()) {
curNode = queue.poll();
System.out.print(curNode.val + " ");
curNum--;
if (curNode.left != null) {
queue.offer(curNode.left);
next++;
}
if (curNode.right != null) {
queue.offer(curNode.right);
next++;
}
if (curNum == 0) {
curNum = next;
next = 0;
System.out.println();//换行
}
}//while
}//printTreeLineByLine
public void buildCompleteTree(int[] nodes) {
Queue<BinaryNode> queue = new LinkedList<BinaryNode>();
int next = 0;//该结点的已构造的子结点个数
root = new BinaryNode(nodes[0]);//用到了root属性
BinaryNode curNode = root;//当前正在构造的结点
int count = 1;//表示当前已构造到的nodes[]的元素下标
while (count < nodes.length) {//这个条件不是while(!queue.isEmpty())
if (next == 2) {
curNode = queue.poll();
next = 0;
}
if (curNode.left == null && count < nodes.length) {
curNode.left = new BinaryNode(nodes[count++]);
queue.offer(curNode.left);
next++;
}
if (curNode.right == null && count < nodes.length) {
curNode.right = new BinaryNode(nodes[count++]);
queue.offer(curNode.right);
next++;
}
}//while
}//buildCompleteTree
public static void main(String[] args) {
Main bst = new Main();
// int[] arr = {2, 4, 5, 1, 3,6,7,8,9,10,12,13,14,15,16,17,18};
int[] arr = {2, 4, 5, 1, 3, 6, 7, 8};
bst.buildCompleteTree(arr);
bst.printTreeLineByLine(bst.root);//用到了root属性
}//main
}
//2
//4 5
//1 3 6 7
//8
参考：http://www.cnblogs.com/hapjin/p/5738354.html
