/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

bfs :

void bfs(TreeNode *root)
{
	if(root==NULL)
		return;	
	queue<TreeNode *> x;
	TreeNode *t;
	x.push(root);
	while(!x.empty()){
		t = x.front();
		if(t->left!=NULL)
			x.push(t->left);
		if(t->right!=NULL)
			x.push(x->right);
		// do something
		x.pop();
	}
}

void dfs(TreeNode *root)
{
	if(root==NULL)
		return;	
	if(root->left != NULL)
		dfs(root->left);
	if(root->right != NULL)
		dfs(root->right);
	// do something
}

void dfs(TreeNode *root)
{
	if(root==NULL)
		return;	
	stack<TreeNode *> x;
	unorder<TreeNode *,bool> m;
	x.push(root);
	while(!x.empty()){
		t = x.top();
		if(t->left != NULL && m[t->left] == 0)
			x.push(t->left);
		else if(t->right != NULL && m[t->right] == 0)
			x.push(t->right);
		else{
			// do something
			m[t] = 1;		
			x.pop();
		}
	}
}

void inorder(TreeNode *root)
{
	if(root==NULL)
		return;	
	if(root->left != NULL)
		inorder(root->left);
	// do something with root

	if(root->right != NULL)
		inorder(root->right);		
}

void inorder(TreeNode *root)
{
	if(root==NULL)
		return;	
	stack<TreeNode *> x;
	unordered_map<TreeNode *,bool> m;
	TreeNode *t;
	x.push(back);
	
	while(!x.empty()){
		t = x.top();
		if(t->left != NULL && m[t->left] == 0){
			t = t-left;
			x.push(t);
		}
		else{
			x.pop();
			m[t] = 1;

			// do something

			if(t->right != NULL)
				x.push(t->right);	
		}
	}		
}

bfs-dfs-bst