Easy_53_257_Binary Tree Paths.java

public class Solution {
    List<String> res = new ArrayList<String>();    
    public List<String> binaryTreePaths(TreeNode root) {
        if(root != null) findPaths(root,String.valueOf(root.val));
        return res;
    }    
    private void findPaths(TreeNode n, String path){
        if(n.left == null && n.right == null) res.add(path);
        if(n.left != null) findPaths(n.left, path+"->"+n.left.val);
        if(n.right != null) findPaths(n.right, path+"->"+n.right.val);
    }
}