5、二叉树

二叉树遍历

递归序

public static void f(Node head) {if (head == null) {return;}f(head.left);f(head.right);
}

前中后遍历_递归

public static void preOrderRecur(Node head) {if (head == null) {return;}System.out.print(head.value + " ");preOrderRecur(head.left);preOrderRecur(head.right);
}public static void inOrderRecur(Node head) {if (head == null) {return;}inOrderRecur(head.left);System.out.print(head.value + " ");inOrderRecur(head.right);
}public static void posOrderRecur(Node head) {if (head == null) {return;}posOrderRecur(head.left);posOrderRecur(head.right);System.out.print(head.value + " ");
}

前中后遍历_非递归

前序遍历

用栈模拟系统所维护的栈。
0）、先把头结点放到栈中
1）、每次弹出一个结点，记为cur
2）、打印cur
3）、如果cur有右、左࿰