Method inorder

TreeInorder.java:2–8

(TreeNode node,List<Integer> list)

class Solution {
    	public void inorder(TreeNode node,List<Integer> list)
	    {
	        if(node==null) return;
	        inorder(node.left,list);
	        list.add(node.val);
	        inorder(node.right,list);
	    }
    public List<Integer> inorderTraversal(TreeNode root) {
        List<Integer> list = new ArrayList<Integer>();
        inorder(root,list);