题解_1

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */


bool isSameTree(struct TreeNode* p, struct TreeNode* q){
	if(p == NULL && q == NULL){
		return true;
	}else if(p == NULL &&  q != NULL){
			return false;
	}else if (p != NULL &&  q == NULL){
		return false;
	}else {
		if(p->val != q->val){
			return false;
		}else {
			return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
		}
	}
}

题解_2

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */


bool isSameTree(struct TreeNode* p, struct TreeNode* q){
	if(!p && !q){
        return true;
    }else if((p && !q) || (!p && q)){
        return false;
    }else{
        if(p->val != q->val){
            return false;
        }else{
            return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
        }
    }
}