二叉树的所有路径

1
/   \
2     3
\
5

[
"1->2->5",
"1->3"
]

/*
* 二叉树的所有路径
*/
public class BinaryTreePaths {
public List<String> binaryTreePaths(TreeNode root) {
// Write your code here
List<String> result = new ArrayList<String>();
if(root==null)
return result;
String s = String.valueOf(root.val);
findPaths(root,s,result);
return result;
}

public void findPaths(TreeNode root,String s, List<String> list)
{
String left = new String();
String right = new String();
if(root.left==null&&root.right==null)
{
list.add(s);
}
if(root.left!=null)
{
left = s+"->"+String.valueOf(root.left.val);
findPaths(root.left, left, list);
}
if(root.right!=null)
{
right = s+"->"+String.valueOf(root.right.val);
findPaths(root.right,right, list);
}

}

}