Same Tree

问题：判断两棵二叉树是否相等

class Solution {

public:

    bool isSameTree(TreeNode *p, TreeNode *q) {

        if(!( (p && q && p->val==q->val) || (p==NULL && q==NULL))) return false;

        if(p==NULL || q==NULL) return true;

        return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);

    }

};