# A weird solution, no extra space, which works !

• Basically I tried to run the search such that each node is considered as root.
So we get all the paths and sub-paths covered.
I am sure it can be optimized,but not able to figure out how !

`````` * Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
private int c=0;
public void pathHelper(TreeNode root, int sum, int cur)
{

if(root.val == sum)c++;
if(root == null)
{
return ;
}

if(root.left != null)
{

path(root.left,sum,root.val);
pathHelper(root.left,sum,0);
}

if(root.right != null)
{

path(root.right,sum,root.val);
pathHelper(root.right,sum,0);
}
}
public void path(TreeNode root, int sum, int cur)
{
if(cur+root.val == sum)
{
c++;
}
if(root == null)
{
return ;
}

if(root.left == null && root.right == null)
{
return;
}
if(root.left != null )
path(root.left,sum,cur+root.val);

if(root.right != null)
path(root.right,sum,cur+root.val);

}
public int pathSum(TreeNode root, int sum) {
if(root == null)return 0;

pathHelper(root,sum,0);
return c;

}
}`````````

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