Java 通过邻接表的前序遍历
我试图将我的EdgeList转换为一个邻接列表,然后按预排序遍历它。我很确定转换到邻接列表的操作是正确的,但是我在遍历它时遇到了一些问题。我曾尝试使用DFS进行此操作,但它给了我错误的结果 以下是我的优势:Java 通过邻接表的前序遍历,java,graph,depth-first-search,adjacency-list,preorder,Java,Graph,Depth First Search,Adjacency List,Preorder,我试图将我的EdgeList转换为一个邻接列表,然后按预排序遍历它。我很确定转换到邻接列表的操作是正确的,但是我在遍历它时遇到了一些问题。我曾尝试使用DFS进行此操作,但它给了我错误的结果 以下是我的优势: {index1=0, index2=2} {index1=3, index2=4} {index1=1, index2=4} {index1=0, index2=5} {index1=2, index2=6} {index1=1, index2=5} {index1=2, index2=7}
{index1=0, index2=2}
{index1=3, index2=4}
{index1=1, index2=4}
{index1=0, index2=5}
{index1=2, index2=6}
{index1=1, index2=5}
{index1=2, index2=7}
这就是链表的样子
0 - 2 - 5
1 - 4 - 5
2 - 6 - 7
3 - 4
或
现在我想对图进行预排序遍历,得到结果0-2-6-7-5-1-4-3
我曾尝试在我的邻接柱状图中使用DFS,但使用以下代码得到的结果是0 2 6 7 5:
public class AdjacencyListGraph {
private int V; // No. of vertices
// Array of lists for Adjacency List Representation
private LinkedList<Integer> adj[];
// Constructor
AdjacencyListGraph(int v) {
V = v;
adj = new LinkedList[v];
for (int i=0; i<v; ++i)
adj[i] = new LinkedList();
}
//Function to add an edge into the graph
void addEdge(int v, int w) {
adj[v].add(w); // Add w to v's list.
}
// A function used by DFS
void DFSUtil(int v,boolean visited[])
{
// Mark the current node as visited and print it
visited[v] = true;
System.out.print(v+" ");
// Recur for all the vertices adjacent to this vertex
Iterator<Integer> i = adj[v].listIterator();
// System.out.println(i.toString());
while (i.hasNext())
{
int n = i.next();
if (!visited[n])
DFSUtil(n,visited);
}
}
// The function to do DFS traversal. It uses recursive DFSUtil()
void DFS(int v)
{
// Mark all the vertices as not visited(set as
// false by default in java)
boolean visited[] = new boolean[V];
// Call the recursive helper function to print DFS traversal
// starting from all vertices one by one
DFSUtil(v, visited);
}
public static void main(String[] args) {
AdjacencyListGraph graph = new AdjacencyListGraph(8);
graph.addEdge(0, 2);
graph.addEdge(0, 5);
graph.addEdge(1, 4);
graph.addEdge(1, 5);
graph.addEdge(2, 6);
graph.addEdge(2, 7);
graph.addEdge(3, 4);
graph.DFS(0);
}
}
我还尝试使用:
void DFS()
{
// Mark all the vertices as not visited(set as
// false by default in java)
boolean visited[] = new boolean[V];
// Call the recursive helper function to print DFS traversal
// starting from all vertices one by one
for (int i=0; i<V; ++i)
if (visited[i] == false)
DFSUtil(i, visited);
}
而不是上面提到的那个,它遍历所有节点,但它返回的结果顺序错误 我做错了什么,如何或应该使用什么来获得所需的结果?尝试以下图表:
graph.addEdge(0, 2);
graph.addEdge(0, 5);
graph.addEdge(1, 4);
graph.addEdge(5, 1); // different direction than original
graph.addEdge(2, 6);
graph.addEdge(2, 7);
graph.addEdge(4, 3); // different direction than original
或者,对程序中的addEdge方法进行轻微修改:
//Function to add an edge into the graph
void addEdge(int v, int w) {
adj[v].add(w); // Add w to v's list.
adj[w].add(v); // Add v to w's list.
}
但是它以错误的顺序返回结果。我在发布的代码中看不到任何返回值。DFS返回无效。
graph.addEdge(0, 2);
graph.addEdge(0, 5);
graph.addEdge(1, 4);
graph.addEdge(5, 1); // different direction than original
graph.addEdge(2, 6);
graph.addEdge(2, 7);
graph.addEdge(4, 3); // different direction than original
//Function to add an edge into the graph
void addEdge(int v, int w) {
adj[v].add(w); // Add w to v's list.
adj[w].add(v); // Add v to w's list.
}