Given two binary trees, write a function to check if they are equal or not.

    Two binary trees are considered equal if they are structurally identical and

the nodes have the same value.

解题代码:

/**
 * Definition for binary tree
 * 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) 
    {
        return p ? ( q && p->val == q->val && isSameTree(p->left,q->left) && isSameTree(p->right,q->right)) : (q == 0) ;
    }
};