Pergunta de entrevista da empresa Newfield Wireless

1) Find if an element is present in a binary tree. 2) Test the syntax of the statement. So for every opening bracket there should be a closing bracket. Sample test cases: (){}[] = Valid ([)] = Invalid ([]) = valid 3) Third problem was related to a 3 by 3 matrix. I could solve the first one but I messed up the 2nd and 3rd