【Leetcode -94.二叉树的中序遍历 -145.二叉树的后序遍历】

		void Inorder(struct TreeNode* root, int* a, int* pos)
		{
		    if (root == NULL)
		        return;
		
		    //先递归当前根的左子树；再将当前根的 val 存放到数组中；最后递归当前根的右子树
		    Inorder(root->left, a, pos);
		    a[(*pos)++] = root->val;
		    Inorder(root->right, a, pos);
		}
		
		
		
		int* inorderTraversal(struct TreeNode* root, int* returnSize)
		{
		    //开辟一个返回中序遍历的数组，pos记录数组的长度
		    int* ret = (int*)malloc(sizeof(int) * 100);
		    int pos = 0;
		
		    //进入中序遍历
		    Inorder(root, ret, &pos);
		    *returnSize = pos;
		    return ret;
		}

		void Postorder(struct TreeNode* root, int* a, int* pos)
		{
		    if (root == NULL)
		        return;
		
		    //先递归当前根的左子树；再递归当前根的右子树；最后将当前根的 val 存放到数组中
		    Postorder(root->left, a, pos);
		    Postorder(root->right, a, pos);
		    a[(*pos)++] = root->val;
		}
		
		
		int* postorderTraversal(struct TreeNode* root, int* returnSize)
		{
		    //开辟返回的数组
		    int* ret = (int*)malloc(sizeof(int) * 100);
		    int pos = 0;
		
		    //进入后序遍历
		    Postorder(root, ret, &pos);
		    *returnSize = pos;
		    return ret;
		}