Leetcode::SameTree

/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode *p, TreeNode *q) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
stack<TreeNode *> s_p,s_q;

if( !p && ! q)
{
return true;
}
else if ( p && q )
{

while( (p && q ) ||( !s_p.empty()&& ! s_q.empty() ))
{
if( p && q)
{
if(p->val != q->val)
{
return false;
}

s_p.push(p);
s_q.push(q);
p=p->left;
q=q->left;
}
else if( !p && !q)
{
p=s_p.top();
q=s_q.top();
s_p.pop();
s_q.pop();
p=p->right;
q=q->right;
}
else
{
return false;
}
}

return true;
}
else
{
return false;
}

}
};

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode *p, TreeNode *q) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if( p == NULL && q == NULL )
{
return true;
}

if( p && q )
{
if( p->val == q->val )
{
return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
}
}

return false;
}
};