[游戏开发]day21--二叉树

1.构造二叉树

构造如图所示的二叉树

public static BinaryCharTree manualConstructTree(){
		
		BinaryCharTree resultTree = new BinaryCharTree('a');	
		BinaryCharTree tempTreeB = new BinaryCharTree('b');
		BinaryCharTree tempTreeC = new BinaryCharTree('c');
		BinaryCharTree tempTreeD = new BinaryCharTree('d');
		BinaryCharTree tempTreeE = new BinaryCharTree('e');
		BinaryCharTree tempTreeF = new BinaryCharTree('f');
		BinaryCharTree tempTreeG = new BinaryCharTree('g');
		
		resultTree.leftChild = tempTreeB;
		resultTree.rightChild = tempTreeC;
		tempTreeB.rightChild = tempTreeD;
		tempTreeC.leftChild = tempTreeE;
		tempTreeD.leftChild = tempTreeF;
		tempTreeD.rightChild = tempTreeG;
		
		return resultTree;
	}

2.遍历二叉树

	//先序遍历
	public void preOrderVisit(){
		System.out.print("" + value + " ");
		
		if(leftChild != null)
			leftChild.preOrderVisit();
		if (rightChild != null) 
			rightChild.preOrderVisit();
	}
	//中序遍历
	public void inOrderVisit(){
		if(leftChild != null)
			leftChild.inOrderVisit();
		System.out.print("" + value + " ");
		
		if(rightChild != null)
			rightChild.inOrderVisit();
	}
	//后序遍历
	public void postOrderVisit(){
		if(leftChild != null)
			leftChild.postOrderVisit();
		if(rightChild != null)
			rightChild.postOrderVisit();
		
		System.out.print("" + value + " ");
	}

3.计算二叉树的深度

public int getDepth() {
		if((leftChild == null)&&(rightChild == null)){
			return 1;
		}
		
		int tempLeftDepth = 0;
		if(leftChild != null){
			tempLeftDepth = leftChild.getDepth();
		}
		
		int tempRightDepth =0;
		if(rightChild != null){
			tempRightDepth = rightChild.getDepth();
		}
		
		if(tempLeftDepth >= tempRightDepth)
			return tempLeftDepth + 1;
		else {
			return tempRightDepth + 1;
		}
		
	}//of getDepth

4.求二叉树的节点个数

public int getNumNodes(){
		if((leftChild == null)&&(rightChild == null)){
			return 1;
		}
		
		int tempLeftNodes = 0;
		if(leftChild != null){
			tempLeftNodes = leftChild.getNumNodes();
		}
		
		int tempRightNodes = 0;
		if(rightChild != null)
			tempRightNodes = rightChild.getNumNodes();
		
		return tempLeftNodes + tempRightNodes + 1;
	}// of getNumNodes

完整代码实现

package datastructure.tree;

import java.util.Arrays;

public class BinaryCharTree{
	char value;
	
	BinaryCharTree leftChild;
	BinaryCharTree rightChild;
	
	public BinaryCharTree(char paraName){
		value = paraName;
		leftChild = null;
		rightChild = null;
	}
	
	public static BinaryCharTree manualConstructTree(){
		
		BinaryCharTree resultTree = new BinaryCharTree('a');
		
		BinaryCharTree tempTreeB = new BinaryCharTree('b');
		BinaryCharTree tempTreeC = new BinaryCharTree('c');
		BinaryCharTree tempTreeD = new BinaryCharTree('d');
		BinaryCharTree tempTreeE = new BinaryCharTree('e');
		BinaryCharTree tempTreeF = new BinaryCharTree('f');
		BinaryCharTree tempTreeG = new BinaryCharTree('g');
		
		resultTree.leftChild = tempTreeB;
		resultTree.rightChild = tempTreeC;
		tempTreeB.rightChild = tempTreeD;
		tempTreeC.leftChild = tempTreeE;
		tempTreeD.leftChild = tempTreeF;
		tempTreeD.rightChild = tempTreeG;
		
		return resultTree;
	}
	
	public void preOrderVisit(){
		System.out.print("" + value + " ");
		
		if(leftChild != null)
			leftChild.preOrderVisit();
		if (rightChild != null) 
			rightChild.preOrderVisit();
	}
	
	public void inOrderVisit(){
		if(leftChild != null)
			leftChild.inOrderVisit();
		System.out.print("" + value + " ");
		
		if(rightChild != null)
			rightChild.inOrderVisit();
	}
	
	public void postOrderVisit(){
		if(leftChild != null)
			leftChild.postOrderVisit();
		if(rightChild != null)
			rightChild.postOrderVisit();
		
		System.out.print("" + value + " ");
	}
	
	public int getDepth() {
		if((leftChild == null)&&(rightChild == null)){
			return 1;
		}
		
		int tempLeftDepth = 0;
		if(leftChild != null){
			tempLeftDepth = leftChild.getDepth();
		}
		
		int tempRightDepth =0;
		if(rightChild != null){
			tempRightDepth = rightChild.getDepth();
		}
		
		if(tempLeftDepth >= tempRightDepth)
			return tempLeftDepth + 1;
		else {
			return tempRightDepth + 1;
		}
		
	}//of getDepth
	
	public int getNumNodes(){
		if((leftChild == null)&&(rightChild == null)){
			return 1;
		}
		
		int tempLeftNodes = 0;
		if(leftChild != null){
			tempLeftNodes = leftChild.getNumNodes();
		}
		
		int tempRightNodes = 0;
		if(rightChild != null)
			tempRightNodes = rightChild.getNumNodes();
		
		return tempLeftNodes + tempRightNodes + 1;
	}// of getNumNodes
	
	public static void main(String args[]) {
		BinaryCharTree tempTree = manualConstructTree();
		System.out.println("\r\nPreorder visit:");
		tempTree.preOrderVisit();
		System.out.println("\r\nIn-order visit:");
		tempTree.inOrderVisit();
		System.out.println("\r\nPost-order visit:");
		tempTree.postOrderVisit();

		System.out.println("\r\n\r\nThe depth is: " + tempTree.getDepth());
		System.out.println("The number of nodes is: " + tempTree.getNumNodes());
	}// of main
}// of class

运行结果：

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