leetcode笔记 100. Same Tree & 101. Symmetric Tree

leetcode刷题14天
100. Same Tree
Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

代码：

class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p==null&&q==null)
        	return true;
        if(p==null||q==null)
        	return false;
        if(p.val != q.val)
        	return false;
        else
        	return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
    }
}

101. Symmetric Tree
     Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).

For example, this binary tree [1,2,2,3,4,4,3] is symmetric:

代码：

class Solution {
    public  boolean isSymmetric(TreeNode p,TreeNode q) {
    	if(p==null&&q==null)
    		return true;
    	if(p==null||q==null)
    		return false;
    	if(p.val == q.val)
    		return isSymmetric(p.left,q.right)&&isSymmetric(p.right,q.left);
    	else 
    		return false;
        
    }	
    public boolean isSymmetric(TreeNode root) {
    	return isSymmetric(root,root);   
    }
}