代码实现：

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     struct TreeNode *left;*     struct TreeNode *right;* };*/
bool compare(struct TreeNode *tree1, struct TreeNode *tree2) {if (tree1 == NULL && tree2 != NULL) {return false;} else if (tree1 != NULL && tree2 == NULL) {return false;} else if (tree1 == NULL && tree2 == NULL) {return true;} else if (tree1->val != tree2->val) {return false;}    // 此时就是：左右节点都不为空，且数值相同的情况// 此时才做递归，做下一层的判断bool compareLeft = compare(tree1->left, tree2->left);       // 左子树：左、 右子树：左bool compareRight = compare(tree1->right, tree2->right);    // 左子树：右、 右子树：右bool isSame = compareLeft && compareRight;                  // 左子树：中、 右子树：中（逻辑处理）return isSame;
}bool isSameTree(struct TreeNode *p, struct TreeNode *q) {return compare(p, q);
}