| 1 | //stack approach |
| 2 | class Solution { |
| 3 | public int minAddToMakeValid(String s) { |
| 4 | Stack<Character> stack = new Stack<>(); |
| 5 | for(int i=0;i<s.length();i++){ |
| 6 | char ch = s.charAt(i); |
| 7 | if(ch == '('){ |
| 8 | stack.push(ch); |
| 9 | } else { |
| 10 | if(stack.isEmpty() || stack.peek()==')') { |
| 11 | stack.push(ch); |
| 12 | } else { |
| 13 | stack.pop(); |
| 14 | } |
| 15 | } |
| 16 | } |
| 17 | return stack.size(); |
| 18 | } |
| 19 | } |
| 20 | |
| 21 | //two pointers |
| 22 | class Solution { |
nothing calls this directly
no outgoing calls
no test coverage detected