摘自《数据结构C++版》,用java实现:
-
package JobInterview_01;
-
-
import java.util.Stack;
-
-
public
class BinaryRecursive {
-
public
static
class Node {
-
public
int value;
-
public Node left;
-
public Node right;
-
-
public Node(int data) {
-
this.value = data;
-
}
-
-
}
-
-
// 前序遍历
-
public static void preOrderRecur(Node head) {
-
if (head ==
null) {
-
return;
-
}
-
System.out.print(head.value +
" ");
-
preOrderRecur(head.left);
-
preOrderRecur(head.right);
-
}
-
-
// 中序遍历
-
public static void inOrderRecur(Node head) {
-
if (head ==
null) {
-
return;
-
}
-
inOrderRecur(head.left);
-
System.out.print(head.value +
" ");
-
inOrderRecur(head.right);
-
-
}
-
-
// 后序遍历
-
public static void posOrderRecur(Node head) {
-
if (head ==
null) {
-
return;
-
}
-
posOrderRecur(head.left);
-
posOrderRecur(head.right);
-
System.out.print(head.value +
" ");
-
-
}
-
//非递归 前序遍历
-
public static void preOrderUnrecur(Node head){
-
System.out.println(
"pre-oder unrecur: ");
-
if (head !=
null) {
-
Stack<Node> stack =
new Stack<Node>();
-
stack.add(head);
-
while(!stack.isEmpty()){
-
head = stack.pop();
-
System.out.print(head.value+
" ");
-
if (head.right!=
null) {
-
stack.push(head.right);
-
}
-
if (head.left !=
null) {
-
stack.push(head.left);
-
}
-
}
-
}
-
System.out.println();
-
}
-
//非递归 中序遍历
-
public static void inOrderUnrecur(Node head){
-
System.out.println(
"in-order unrecur:");
-
if (head !=
null) {
-
Stack<Node> stack =
new Stack<Node>();
-
while (!stack.isEmpty() || head !=
null) {
-
if(head !=
null){
-
stack.push(head);
-
head = head.left;
-
}
-
else {
-
head = stack.pop();
-
System.out.print(head.value+
" ");
-
head = head.right;
-
}
-
}
-
}
-
System.out.println();
-
}
-
public static void posOrderUnRecur1(Node head) {
-
System.out.print(
"pos-order unrecur: ");
-
if (head !=
null) {
-
Stack<Node> s1 =
new Stack<Node>();
-
Stack<Node> s2 =
new Stack<Node>();
-
s1.push(head);
-
while (!s1.isEmpty()) {
-
head = s1.pop();
-
s2.push(head);
-
if (head.left !=
null) {
-
s1.push(head.left);
-
}
-
if (head.right !=
null) {
-
s1.push(head.right);
-
}
-
}
-
while (!s2.isEmpty()) {
-
System.out.print(s2.pop().value +
" ");
-
}
-
}
-
System.out.println();
-
}
-
-
public static void main(String[] args) {
-
Node head =
new Node(
5);
-
head.left =
new Node(
3);
-
head.right =
new Node(
8);
-
head.left.left =
new Node(
2);
-
head.left.right =
new Node(
4);
-
head.left.left.left =
new Node(
1);
-
head.right.left =
new Node(
7);
-
head.right.left.left =
new Node(
6);
-
head.right.right =
new Node(
10);
-
head.right.right.left =
new Node(
9);
-
head.right.right.right =
new Node(
11);
-
-
-
preOrderRecur(head);
-
System.out.println();
-
preOrderUnrecur(head);
-
-
System.out.println(
"in-order:");
-
inOrderRecur(head);
-
System.out.println();
-
inOrderUnrecur(head);
-
-
System.out.println(
"pos order :");
-
posOrderRecur(head);
-
System.out.println();
-
posOrderUnRecur1(head);
-
-
}
-
-
}
-