Leetcode::SameTree

同时遍历两个树；

/**
* 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;
}

}
};

 

 

递归实现：

/**
 * 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;
    }
};