学习第24天

学习Java第24天

二叉树的建立

只增加了一个构造方法, 相当于第 22 天的逆过程.
保留了调拭语句, 因为下标很容易出错.
使用一个线性表先分配所有节点的空间, 再将节点链接起来.
最后并没有返回, 而是把第 0 个节点的相应值拷贝给自己.

代码如下：

public class BinaryCharTree24 {

	public BinaryCharTree(char[] paraDataArray, int[] paraIndicesArray) {
		// Step 1. Use a sequential list to store all nodes.
		int tempNumNodes = paraDataArray.length;
		BinaryCharTree[] tempAllNodes = new BinaryCharTree[tempNumNodes];
		for (int i = 0; i < tempNumNodes; i++) {
			tempAllNodes[i] = new BinaryCharTree(paraDataArray[i]);
		} //i

		// Step 2. Link these nodes.
		for (int i = 1; i < tempNumNodes; i++) {
			for (int j = 0; j < i; j++) {
				System.out.println("indices " + paraIndicesArray[j] + " vs. " + paraIndicesArray[i]);
				if (paraIndicesArray[i] == paraIndicesArray[j] * 2 + 1) {
					tempAllNodes[j].leftChild = tempAllNodes[i];
					System.out.println("Linking " + j + " with " + i);
					break;
				} else if (paraIndicesArray[i] == paraIndicesArray[j] * 2 + 2) {
					tempAllNodes[j].rightChild = tempAllNodes[i];
					System.out.println("Linking " + j + " with " + i);
					break;
				} //if
			} //j
		} //i
		
		//Step 3. The root is the first node.
		value = tempAllNodes[0].value;
		leftChild = tempAllNodes[0].leftChild;
		rightChild = tempAllNodes[0].rightChild;
	}//the the second constructor


	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());

		tempTree.toDataArrays();
		System.out.println("The values are: " + Arrays.toString(tempTree.valuesArray));
		System.out.println("The indices are: " + Arrays.toString(tempTree.indicesArray));

		tempTree.toDataArraysObjectQueue();
		System.out.println("Only object queue.");
		System.out.println("The values are: " + Arrays.toString(tempTree.valuesArray));
		System.out.println("The indices are: " + Arrays.toString(tempTree.indicesArray));
		
		char[] tempCharArray = {'A', 'B', 'C', 'D', 'E', 'F'};
		int[] tempIndicesArray = {0, 1, 2, 4, 5, 12};
		BinaryCharTree tempTree2 = new BinaryCharTree(tempCharArray, tempIndicesArray);

		System.out.println("\r\nPreorder visit:");
		tempTree2.preOrderVisit();
		System.out.println("\r\nIn-order visit:");
		tempTree2.inOrderVisit();
		System.out.println("\r\nPost-order visit:");
		tempTree2.postOrderVisit();
	}//main

}

有点难以吃透二叉树