Problem Description
Given a binary tree, return the inorder traversal of its nodes' values.
Problem Constraints
1 <= number of nodes <= 105.
Input Format
First and only argument is root node of the binary tree, A.
Output Format
Return an integer array denoting the inorder traversal of the given binary tree.
/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
vector<int> Solution::inorderTraversal(TreeNode* root) {
    stack<TreeNode*> stack;
    vector<int>myvec;
    
	TreeNode *curr=root; 
	while(!stack.empty() || curr!=NULL)
	{
		/*If current node is not NULL push the node in stack*/
		if(curr!=NULL)              
		{
			stack.push(curr);
			curr=curr->left;
		}
		/*If current node is empty or NULL pop it from the stack */
		else                        
		{
			curr=stack.top();
			stack.pop();
			myvec.push_back(curr->val);
			curr=curr->right;
		}
	}
return myvec;
}