Morris遍历

描述

分析

Code

public static void morris(Node head) {
		if (head == null) {
			return;
		}
		Node cur = head;
		Node mostRight = null;
		while (cur != null) {//过流程
			mostRight = cur.left;//mostRight是cur的左孩子
			if (mostRight != null) {//有左子树
				while (mostRight.right != null && mostRight.right != cur) {
					mostRight = mostRight.right;
				}
				//mostRight变成了cur左子树，最右的节点
				if (mostRight.right == null) {//这是第一次来到cur
					mostRight.right = cur;
					cur = cur.left;
					continue;
				} else {//mostRight.right == cur
					mostRight.right = null;
				}
			}
			cur = cur.right;
		}
	}

先序Morris

Code

public static void morrisPre(Node head) {
		if (head == null) {
			return;
		}
		Node cur1 = head;
		Node mostRight = null;
		while (cur1 != null) {
			mostRight = cur1.left;
			if (mostRight != null) {//有左子树
				while (mostRight.right != null && mostRight.right != cur1) {
					mostRight = mostRight.right;
				}
				if (mostRight.right == null) {
					mostRight.right = cur1;
					System.out.print(cur1.value + " ");
					cur1 = cur1.left;
					continue;
				} else {
					mostRight.right = null;
				}
			} else {//没有左子树的情况
				System.out.print(cur1.value + " ");
			}
			cur1 = cur1.right;
		}
		System.out.println();
	}

中序Morris

Code

public static void morrisIn(Node head) {
		if (head == null) {
			return;
		}
		Node cur1 = head;
		Node mostRight = null;
		while (cur1 != null) {
			mostRight = cur1.left;
			if (mostRight != null) {//有左子树
				while (mostRight.right != null && mostRight.right != cur1) {
					mostRight = mostRight.right;
				}
				if (mostRight.right == null) {//第一次来到cur
					mostRight.right = cur1;
					cur1 = cur1.left;
					continue;
				} else {
					mostRight.right = null;
				}
			}
			System.out.print(cur1.value + " ");
			cur1 = cur1.right;
		}
		System.out.println();
	}

后序Morris

Code

public static void morrisPos(Node head) {
		if (head == null) {
			return;
		}
		Node cur1 = head;
		Node mostRight = null;
		while (cur1 != null) {
			mostRight = cur1.left;
			if (mostRight != null) {
				while (mostRight.right != null && mostRight.right != cur1) {
					mostRight = mostRight.right;
				}
				if (mostRight.right == null) {
					mostRight.right = cur1;
					cur1 = cur1.left;
					continue;
				} else {
					mostRight.right = null;
					printEdge(cur1.left);
				}
			}
			cur1 = cur1.right;
		}
		printEdge(head);
		System.out.println();
	}

	public static void printEdge(Node head) {
		Node tail = reverseEdge(head);
		Node cur = tail;
		while (cur != null) {
			System.out.print(cur.value + " ");
			cur = cur.right;
		}
		reverseEdge(tail);
	}

	public static Node reverseEdge(Node from) {
		Node pre = null;
		Node next = null;
		while (from != null) {
			next = from.right;
			from.right = pre;
			pre = from;
			from = next;
		}
		return pre;
	}