Leetcode 100 Same Tree 二叉树

就是判断两棵树的值和结构是否相同

注意：要判断是否所有的树节点是否为NULL

 /**
  * Definition for a binary tree node.
  * struct TreeNode {
  *     int val;
  *     TreeNode *left;
  *     TreeNode *right;
  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
  * };
  */
 class Solution {
 public:
     bool isSameTree(TreeNode* p, TreeNode* q) {
         if(!p && !q) {
             return true;
         }
         else if(!p||!q){
             return false;
         }
         else{
             if(p->val != q->val) return false;
             else return isSameTree(p->left, q->left) && 
                           isSameTree(p->right, q->right);
         }
     }
 };