JAVA数据结构实验之二叉树五：层序遍历

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数据结构实验之二叉树五：层序遍历

Time Limit: 1000 ms Memory Limit: 65536 KiB

Submit Statistic

Problem Description

已知一个按先序输入的字符序列，如abd,,eg,,,cf,,,(其中,表示空结点)。请建立二叉树并求二叉树的层次遍历序列。

Input

 输入数据有多行，第一行是一个整数t (t<1000)，代表有t行测试数据。每行是一个长度小于50个字符的字符串。

Output

 输出二叉树的层次遍历序列。

Sample Input

2
abd,,eg,,,cf,,,
xnl,,i,,u,,

Sample Output

abcdefg
xnuli

Hint

 

Source

xam

import java.io.*;
import java.util.*;

class Main {

	public static void main(String[] args) throws IOException {
		sc.in(System.in);
		// while (!sc.to.hasMoreTokens()) {
		int t = sc.nextInt();
		while (t-- > 0) {
			BT<Character> bt = new BT<>();
			LinkedList<Character> Tree = new LinkedList<>();
			String s = sc.next();
			char[] c = s.toCharArray();
			for (int i = 0; i < c.length; i++) {
				if (c[i] == ',')
					Tree.add(null);
				else
					Tree.add(c[i]);
			}
			TN<Character> root = bt.CBP(Tree);
			bt.LevelOrder(root);
			System.out.println();
		}

	}

}

class BT<T> {
	public TN<T> CBP(LinkedList<T> data) {
		TN<T> root = null;
		T d = data.removeFirst();
		if (d != null) {
			root = new TN<T>(d, null, null);
			root.l = CBP(data);
			root.r = CBP(data);
		}
		return root;
	}

	public void PreOrder(TN<T> root) {
		if (root != null) {
			System.out.print(root.d);
			PreOrder(root.l);
			PreOrder(root.r);
		}
	}

	public void InOrder(TN<T> root) {
		if (root != null) {
			InOrder(root.l);
			System.out.print(root.d);
			InOrder(root.r);
		}
	}

	public void PostOrder(TN<T> root) {
		if (root != null) {
			PostOrder(root.l);
			PostOrder(root.r);
			System.out.print(root.d);
		}
	}

	public void LevelOrder(TN<T> root) {
		if(root==null) return;
		LinkedList<TN> queue = new LinkedList<>();
		TN<T> p;
		queue.add(root);
		while (!queue.isEmpty()) {
			p = queue.removeFirst();
			System.out.print(p.d);
			if (p.l != null) {
				queue.add(p.l);
			}
			if (p.r != null) {
				queue.add(p.r);
			}
		}
	}

}

class TN<T> {
	public T d;
	public TN<T> l;
	public TN<T> r;

	public TN(T d, TN<T> l, TN<T> r) {
		this.d = d;
		this.l = l;
		this.r = r;
	}
}

class sc {
	static BufferedReader re;
	static StringTokenizer to;

	static void in(InputStream in) {
		re = new BufferedReader(new InputStreamReader(in), 32678);
		to = new StringTokenizer("");
	}

	static String next() throws IOException {
		while (!to.hasMoreTokens()) {
			to = new StringTokenizer(re.readLine());
		}
		return to.nextToken();
	}

	static int nextInt() throws IOException {
		return Integer.parseInt(next());
	}

	static double nextDouble() throws IOException {
		return Double.parseDouble(next());
	}
}