| 1 | class Solution { |
| 2 | public boolean parseBoolExpr(String expression) { |
| 3 | // 2n |
| 4 | Stack<Character> stack = new Stack<>(); |
| 5 | int n = expression.length(); |
| 6 | // n + n |
| 7 | for(int i=0;i<n;i++){ //N |
| 8 | char ch = expression.charAt(i); |
| 9 | if(ch==')'){ |
| 10 | ArrayList<Character> list = new ArrayList<>(); |
| 11 | while(stack.peek()!='('){ //k |
| 12 | list.add(stack.pop()); |
| 13 | } |
| 14 | stack.pop(); //remove '(' |
| 15 | char op = stack.pop(); |
| 16 | char ans = evaluate(list,op); //k |
| 17 | stack.push(ans); |
| 18 | }else{ |
| 19 | if(ch!=','){ |
| 20 | stack.push(ch); |
| 21 | } |
| 22 | } |
| 23 | } |
| 24 | return stack.peek() == 't'; |
| 25 | } |
| 26 | public char evaluate(ArrayList<Character> list ,char op){ |
| 27 | if(op == '&'){ |
| 28 | if(find(list,'f')){ |