题解 | #二叉树的中序遍历#

int pre_seq[1000] = {0}, i = 0;
int* inorderTraversal(struct TreeNode* root, int* returnSize ) {
    if(root != NULL){
        inorderTraversal(root->left, returnSize);
        pre_seq[i++] = root->val;
        inorderTraversal(root->right, returnSize);
    }
    *returnSize = i;
    return pre_seq;
}
//有点好奇递归过程当中也返回了pre_seq指针为啥不打印