数据结构：广义表的实现(Java)

广义表的简单理解在这篇博文中：https://blog.csdn.net/lishanleilixin/article/details/87364496，在此不做赘述。

Java实现广义表：

package 广义表;

import java.util.Stack;

public class Test {

	public final int TAG_TABLE = 1;
	public final int TAG_ITEM = 0;

	private char mStartSymb = '(';
	private char mEndSymb = ')';
	private Node mGenTable;

	class Node {
		int tag;
		Object data;
		Node mPh;
		Node mPt;

		public Node(Node ph, Node pt, int tag, Object data) {
			this.mPh = ph;
			this.mPt = pt;
			this.tag = tag;
			this.data = data;
		}
	}

	public Test(String genTable) {
		if(genTable == null)
			throw new NullPointerException("genTable is null");
		initTable(genTable);
	}

	public Test() {
		mGenTable = new Node(null, null, TAG_TABLE, null);

	}

	public Test(Test b) {
		if(b != null) {
			mGenTable = b.mGenTable;
		}
	}

	public void initTable(String genTable) {
		String ts = genTable.replaceAll("\\s", "");
		int len = ts.length();
		Stack<Character> symStack = new Stack<Character>();
		Stack<Node> nodeStack = new Stack<Node>();
		initSymbolicCharactor(ts);
		mGenTable = new Node(null, null, TAG_TABLE, null);
		Node itemNode, tableNode = mGenTable, tmpNode;
		for (int i = 0; i < len; i++) {
			if(ts.charAt(i) == mStartSymb) {
				tmpNode = new Node(null, null ,TAG_TABLE, null);
				symStack.push(ts.charAt(i));
				if(symStack.size() > 1) {
					nodeStack.push(tableNode);
					tableNode.mPh = tmpNode;
					tableNode = tableNode.mPh;
				}
				else {
					tableNode.mPt = tmpNode;
					tableNode = tableNode.mPt;
				}
			}
			else if(ts.charAt(i) == mEndSymb) {
				if(symStack.isEmpty()) {
					throw new NullPointerException(
							"IllegalArgumentException in constructor GeneralizedTable!...");
				}
				if(symStack.size() > 1) {
					tableNode = nodeStack.pop();
				}
				symStack.pop();
			}
			else if(ts.charAt(i) == ',') {
				tableNode.mPt = new Node(null, null, TAG_TABLE, null);
				tableNode = tableNode.mPt;
			}
			else {
				itemNode = new Node(null, null, TAG_ITEM, ts.charAt(i));
				tableNode.mPh = itemNode;
			}
		}

		if(!symStack.isEmpty()) {
			throw new NullPointerException(
					"IllegalArgumentException in constructor GeneralizedTable!...");
		}

	}

	public void initSymbolicCharactor(String ts) {
		mStartSymb = ts.charAt(0);
		switch (mStartSymb) {
		    case '(':
		    	mEndSymb = ')';
		    	break;
		    case '{':
		    	mEndSymb = '}';
		    	break;
		    case '[':
		    	mEndSymb = ']';
		    	break;
		    default:
		    	throw new IllegalArgumentException(
                        "IllegalArgumentException ---> initSymbolicCharactor");
		}

	}

	public void print() {
		print(mGenTable);
	}

	private void print(Node node) {
		if(node == null) return;
		if(node.tag == 0) System.out.print(node.data.toString() + "\t");
		print(node.mPh);
		print(node.mPt);
	}

	public int depth() {
		if(mGenTable == null)
			throw new NullPointerException("Generalized Table is null !.. ---> method depth");
		return depth(mGenTable);
	}

	private int depth(Node node) {
		if(node == null || node.tag == 0) return 0;
		int depHeader = 0, depTear = 0;
		depHeader = 1 + depth(node.mPh);
		depTear = depth(node.mPt);
		return depHeader > depTear ? depHeader : depTear;
	}

	public int length() {
		if(mGenTable == null || mGenTable.mPt == null) return -1;
		int len = 0;
		Node node = mGenTable;
		while(node.mPt != null) {
			node = node.mPt;
			if(node.mPh == null && node.mPt == null) break;
			len++;
		}
		return len;
	}

	public Test getHeader() {
		if(isEmpty()) return null;
		Node node = mGenTable.mPt;
		Test test = new Test();
		test.mGenTable.mPt = node.mPh;
		return test;
	} 

	public Test getTear() {
		if(mGenTable == null) return null;
		Node node = mGenTable.mPt;
		Test test = new Test();
		test.mGenTable.mPt = node.mPt;
		return test;

	}

	public boolean isEmpty() {
		if(mGenTable == null) return true;
		Node node = mGenTable.mPt;
		return node.mPh == null || node.mPt == null;
	}

	public static void main(String[] args) {
		Test test = new Test("(c,a,b,(a,b,c),(a,(a,b),c))");
		test.print();
		System.out.println();
		System.out.println("该广义表的深度为:" + test.depth());
		System.out.println("该广义表的长度为:" + test.length());

		Test t2 = test.getTear();
		t2.print();
	}

}