java学习第34天，图的深度优先遍历

与二叉树的深度优先遍历类似。不过比二叉树的深度优先遍历要复杂一些。
1，使用到了图连通性检测代码。

package java31to40;

import java21to30.D22_CircleObjectQueue;
import java21to30.D25_ObjectStack;

public class D32_Graph {
	D31_IntMatrix connectivityMatrix;

	public static void main(String[] args) {
		System.out.println("Hello!");
		D32_Graph tempGraph = new D32_Graph(3);
		System.out.println(tempGraph);
		getConnectivityTest();
	}

	public D32_Graph(int paraNumNodes) {
		connectivityMatrix = new D31_IntMatrix(paraNumNodes, paraNumNodes);
	}

	public D32_Graph(int[][] paraMatrix) {
		connectivityMatrix = new D31_IntMatrix(paraMatrix);
	}

	public String toString() {
		String resultString = "图的连通性矩阵.\r\n" + connectivityMatrix;
		return resultString;
	}

	public boolean getConnectivity() throws Exception {
		D31_IntMatrix tempConnectivityMatrix = D31_IntMatrix.getIdentityMatrix(connectivityMatrix.getData().length);
		D31_IntMatrix tempMultipliedMatrix = new D31_IntMatrix(connectivityMatrix);
		for (int i = 0; i < connectivityMatrix.getData().length - 1; i++) {
			tempConnectivityMatrix.add(tempMultipliedMatrix);
			tempMultipliedMatrix = D31_IntMatrix.multiply(tempMultipliedMatrix, connectivityMatrix);
		}
		System.out.println("连通性矩阵为: " + tempConnectivityMatrix);
		int[][] tempData = tempConnectivityMatrix.getData();
		for (int i = 0; i < tempData.length; i++) {
			for (int j = 0; j < tempData.length; j++) {
				if (tempData[i][j] == 0) {
					System.out.println("节点 " + i + " 不能到达 " + j);
					return false;
				}
			}
		}
		return true;
	}

	public static void getConnectivityTest() {
		int[][] tempMatrix = { { 0, 1, 0 }, { 1, 0, 1 }, { 0, 1, 0 } };
		D32_Graph tempGraph2 = new D32_Graph(tempMatrix);
		System.out.println(tempGraph2);
		boolean tempConnected = false;
		try {
			tempConnected = tempGraph2.getConnectivity();
		} catch (Exception ee) {
			System.out.println(ee);
		}
		System.out.println("图是否具有连通性? " + tempConnected);
		tempGraph2.connectivityMatrix.setValue(1, 0, 0);
		tempConnected = false;
		try {
			tempConnected = tempGraph2.getConnectivity();
		} catch (Exception ee) {
			System.out.println(ee);
		}
		System.out.println("图是否具有连通性? " + tempConnected);
	}

	public String breadthFirstTraversal(int paraStartIndex) {
		D22_CircleObjectQueue tempQueue = new D22_CircleObjectQueue();
		String resultString = "";
		int tempNumNodes = connectivityMatrix.getRows();
		boolean[] tempVisitedArray = new boolean[tempNumNodes];
		tempVisitedArray[paraStartIndex] = true;
		tempVisitedArray[paraStartIndex] = true;
		resultString += paraStartIndex;
		tempQueue.enqueue(new Integer(paraStartIndex));
		int tempIndex;
		Integer tempInteger = (Integer) tempQueue.dequeue();
		while (tempInteger != null) {
			tempIndex = tempInteger.intValue();
			for (int i = 0; i < tempNumNodes; i++) {
				if (tempVisitedArray[i]) {
					continue;
				}
				if (connectivityMatrix.getData()[tempIndex][i] == 0) {
					continue;
				}
				tempVisitedArray[i] = true;
				resultString += i;
				tempQueue.enqueue(new Integer(i));
			}
			tempInteger = (Integer) tempQueue.dequeue();
		}
		return resultString;
	}

	public String depthFirstTraversal(int paraStartIndex) {
		D25_ObjectStack tempStack = new D25_ObjectStack();
		String resultString = "";
		int tempNumNodes = connectivityMatrix.getRows();
		boolean[] tempVisitedArray = new boolean[tempNumNodes];
		tempVisitedArray[paraStartIndex] = true;
		resultString += paraStartIndex;
		tempStack.push(new Integer(paraStartIndex));
		System.out.println("Push " + paraStartIndex);
		System.out.println("Visited " + resultString);
		int tempIndex = paraStartIndex;
		int tempNext;
		Integer tempInteger;
		while (true) {
			tempNext = -1;
			for (int i = 0; i < tempNumNodes; i++) {
				if (tempVisitedArray[i]) {
					continue;
				}
				if (connectivityMatrix.getData()[tempIndex][i] == 0) {
					continue;
				}
				tempVisitedArray[i] = true;
				resultString += i;
				tempStack.push(new Integer(i));
				System.out.println("Push " + i);
				tempNext = i;
				break;
			}
			if (tempNext == -1) {
				if (tempStack.isEmpty()) {
					break;
				}
				tempInteger = (Integer) tempStack.pop();
				System.out.println("Pop " + tempInteger);
				tempIndex = tempInteger.intValue();
			} else {
				tempIndex = tempNext;
			}
		}
		return resultString;
	}
}

2，图的深度优先遍历代码

package java31to40;

public class D34_DepthFirstTraversal {
	public static void depthFirstTraversalTest() {
		int[][] tempMatrix = { { 0, 1, 1, 0 }, { 1, 0, 0, 1 }, { 1, 0, 0, 0 }, { 0, 1, 0, 0 } };
		D32_Graph tempGraph = new D32_Graph(tempMatrix);
		System.out.println(tempGraph);
		String tempSequence = "";
		try {
			tempSequence = tempGraph.depthFirstTraversal(0);
		} catch (Exception ee) {
			System.out.println(ee);
		}
		System.out.println("图的深度优先遍历访问顺序:: " + tempSequence);
	}

	public static void main(String[] args) {
		System.out.println("Hello!");
		D32_Graph tempGraph = new D32_Graph(3);
		System.out.println(tempGraph);
		D32_Graph.getConnectivityTest();
		D33_BreadthFirstTraversal.breadthFirstTraversalTest();
		depthFirstTraversalTest();
	}
}

结果输出：

Hello!
图的连通性矩阵.
[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
图的连通性矩阵.
[[0, 1, 0], [1, 0, 1], [0, 1, 0]]
连通性矩阵为: [[2, 1, 1], [1, 3, 1], [1, 1, 2]]
图是否具有连通性? true
连通性矩阵为: [[1, 1, 1], [0, 2, 1], [0, 1, 2]]
节点 1 不能到达 0
图是否具有连通性? false
图的连通性矩阵.
[[0, 1, 1, 0], [1, 0, 0, 1], [1, 0, 0, 1], [0, 1, 1, 0]]
图的广度优先遍历访问顺序: 2031
图的连通性矩阵.
[[0, 1, 1, 0], [1, 0, 0, 1], [1, 0, 0, 0], [0, 1, 0, 0]]
Push 0
Visited 0
Push 1
Push 3
Pop 3
Pop 1
Pop 0
Push 2
Pop 2
图的深度优先遍历访问顺序:: 0132