面试总结2

1、MySQL查询方式：https://www.cnblogs.com/bypp/p/7755307.html

2、hhvm

3、如何判断一个二叉树是否为二叉搜索树

中序遍历：

　　/**
    * Definition for binary tree
    * public class TreeNode {
    * int val;
    * TreeNode left;
    * TreeNode right;
    * TreeNode(int x) { val = x; }
    * }
    */
    import java.util.*;
    public class Solution {
        public boolean isValidBST(TreeNode root) {
            ArrayList<TreeNode> list = new ArrayList<TreeNode>();
            if(root ==null){
                return true;
            }
            inorder(root,list);
            for(int i=0;i<list.size()-1;i++){
                if(list.get(i).val>=list.get(i+1).val){
                    return false;
                }
            }
            return true;
        }
        
        public static void inorder(TreeNode root,ArrayList<TreeNode> list){
            if(root!=null){
                inorder(root.left,list);
                list.add(root);
                inorder(root.right,list);
            }
        }
    }

4、二叉树层次遍历

	public void levelIterator(TreeNode n){  
		Queue<TreeNode> queue = new LinkedList<TreeNode>();  
		queue.offer(n);  
		while (!queue.isEmpty()) {  
			TreeNode t = queue.poll();  
			if (t !=null) {  
				System.out.println("key:"+t.key+"--name:"+t.data);
			}  
			if (t.leftChild !=null) {  
				queue.offer(t.leftChild);  
			}  
			if (t.rightChild !=null) {  
				queue.offer(t.rightChild);  
			}
		}
	}  

5、二叉树非递归后续遍历

//前序遍历的非递归实现  
        public void nonRecPreOrder(TreeNode p){    
            Stack<TreeNode> stack=new Stack<TreeNode>();    
            TreeNode node=p;    
            while(node!=null||stack.size()>0){    
                while(node!=null){    
                    System.out.println("key:"+node.key+"--name:"+node.data);;     
                    stack.push(node);   
                    node=node.leftChild;    
                }    
                if(stack.size()>0){   
                    node=stack.pop();    
                    node=node.rightChild;   
                }    
            }    
        } 

 

//中序遍历的非递归实现    
        public void nonRecInOrder(TreeNode p){    
            Stack<TreeNode> stack =new Stack<TreeNode>();    
            TreeNode node =p;    
            while(node!=null||stack.size()>0){    
                //存在左子树    
                while(node!=null){    
                    stack.push(node);    
                    node=node.leftChild;    
                }    
                //栈非空    
                if(stack.size()>0){    
                    node=stack.pop();    

　　　　　　System.out.println("key:"+node.key+"--name:"+node.data);  

                    node=node.rightChild;    
                }    
            }    
        }    

//后序遍历的非递归实现    
    public void noRecPostOrder(TreeNode p){    
        Stack<TreeNode> stack=new Stack<TreeNode>();    
        TreeNode node =p;    
        while(p!=null){    
            //左子树入栈    
            for(;p.leftChild!=null;p=p.leftChild){    
                stack.push(p);    
            }    
            //当前结点无右子树或右子树已经输出    
            while(p!=null&&(p.rightChild==null||p.rightChild==node)){    
                System.out.println("key:"+p.key+"--name:"+p.data);;        
                //纪录上一个已输出结点    
                node =p;    
                if(stack.empty())    
                    return;    
                p=stack.pop();    
            }    
            //处理右子树    
            stack.push(p);    
            p=p.rightChild;    
        }    
    }

6、php-fpm的运行方式

7、Innodb和missame 所有有什么区别