LV2. 쇠막대기

class Solution{
	public int solution(String arrangement) {
		int answer = 0;
		
		String[] arr = arrangement.split("");
		
		LinkedList<Integer> stackOpen = new LinkedList<>();
		
		int startIndex = 0;
		int endIndex = 0;
		
		for(int i=0; i<arr.length-1; i++) {
			if(arr[i].equals("(") && arr[i+1].equals("(")) {
				stackOpen.push(i);
			}
			
			if(arr[i].equals(")") && arr[i+1].equals(")")) {
				startIndex = stackOpen.pop();
				endIndex = i+1;
				answer += countRazer(arr, startIndex, endIndex);
			}
		}
		
		return answer;
	}

	private int countRazer(String[] arr, int startIndex, int endIndex) {
		int count = 0;

		for(int i=startIndex; i<endIndex; i++) {
			if(arr[i].equals("(") && arr[i+1].equals(")")) {
				count++;
			}
		}
		
		return count+1;
	}

}

class Solution {
    public static int solution(String arrangement) {
        int answer = 0;
        Stack<Integer> st = new Stack<>();
        for (int i = 0; i < arrangement.length(); i++) {
            if (arrangement.charAt(i) == '(') {
                st.push(i);
            } else if (arrangement.charAt(i) == ')') {
                if (st.peek() + 1 == i) {
                    st.pop();
                    answer += st.size();
                } else {
                    st.pop();
                    answer += 1;
                }
            }
        }
        return answer;
    }
}