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);
    }
};