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 ArrayList<Integer> inorder(Node root) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        if(root == null) {
            return list;
        }
        ArrayList<Integer> leftList = inorder(root.left);
        ArrayList<Integer> rightList = inorder(root.right);
        leftList.add(root.data);
        leftList.addAll(rightList);
        return leftList;
    }    
 
 
    boolean checkBST(Node root) {
       ArrayList<Integer> list = inorder(root);
       List tmp = new ArrayList(list);
       java.util.Collections.sort(tmp);
       return tmp.equals(list);
    }

Main.java:1: error: class, interface, or enum expected
 ArrayList<Integer> inorder(Node root) {
 ^
Main.java:3: error: class, interface, or enum expected
        if(root == null) {
        ^
Main.java:5: error: class, interface, or enum expected
        }
        ^
Main.java:7: error: class, interface, or enum expected
        ArrayList<Integer> rightList = inorder(root.right);
        ^
Main.java:8: error: class, interface, or enum expected
        leftList.add(root.data);
        ^
Main.java:9: error: class, interface, or enum expected
        leftList.addAll(rightList);
        ^
Main.java:10: error: class, interface, or enum expected
        return leftList;
        ^
Main.java:11: error: class, interface, or enum expected
    }    
    ^
Main.java:16: error: class, interface, or enum expected
       List tmp = new ArrayList(list);
       ^
Main.java:17: error: class, interface, or enum expected
       java.util.Collections.sort(tmp);
       ^
Main.java:18: error: class, interface, or enum expected
       return tmp.equals(list);
       ^
Main.java:19: error: class, interface, or enum expected
    }
    ^
12 errors

Standard output is empty