数据结构与算法二叉树广度遍历

Posted 2020-09-24

二叉树的广度遍历想想还是比較简单的。利用队列存储当前结点的左儿子和右儿子用作未来的訪问。

• 代码实现

/**
 * 源代码名称：TreeBFS.java 
 * 日期：2014-08-25 
 * 程序功能：二叉树广度遍历 
 * 版权：[email protected] 
 * 作者：A2BGeek
 */
import java.util.LinkedList;
import java.util.Queue;

public class TreeBFS {
	class TreeNode<T> {
		private T mNodeData;
		private TreeNode<T> mLeftChild;
		private TreeNode<T> mRightChild;

		public TreeNode(T data, TreeNode<T> left, TreeNode<T> right) {
			// TODO Auto-generated constructor stub
			mNodeData = data;
			mLeftChild = left;
			mRightChild = right;
		}

		public T getData() {
			return mNodeData;
		}

		public void setData(T data) {
			mNodeData = data;
		}

		public TreeNode<T> getLeft() {
			return mLeftChild;
		}

		public void setLeft(TreeNode<T> left) {
			mLeftChild = left;
		}

		public TreeNode<T> getRight() {
			return mRightChild;
		}

		public void setRight(TreeNode<T> right) {
			mRightChild = right;
		}
	}

	public TreeNode<String> createTree() {
		TreeNode<String> h = new TreeNode<String>("h", null, null);
		TreeNode<String> g = new TreeNode<String>("g", null, null);
		TreeNode<String> f = new TreeNode<String>("f", null, null);
		TreeNode<String> e = new TreeNode<String>("e", null, null);
		TreeNode<String> d = new TreeNode<String>("d", null, h);
		TreeNode<String> c = new TreeNode<String>("c", f, g);
		TreeNode<String> b = new TreeNode<String>("b", d, e);
		TreeNode<String> a = new TreeNode<String>("a", b, c);
		return a;
	}

	public void BFSIterate(TreeNode<String> root) {
		Queue<TreeNode<String>> queue = new LinkedList<TreeNode<String>>();
		queue.offer(root);
		while (!queue.isEmpty()) {
			TreeNode<String> node = queue.poll();
			System.out.print(node.getData() + " ");
			if (node.getLeft() != null) {
				queue.offer(node.getLeft());
			}
			if (node.getRight() != null) {
				queue.offer(node.getRight());
			}
		}
	}

	public static void main(String[] args) {
		TreeBFS treeBFS = new TreeBFS();
		TreeNode<String> root = treeBFS.createTree();
		treeBFS.BFSIterate(root);
	}
}