Java实现括号匹配

import java.util.*;

public class Main {
	
	public static void main(String[] args) {
		Stack<String> stack=new Stack<String>();
		String s=")()))";
		String[] arr=s.split("");
		int num=0;
		for(int i=0;i<arr.length;i++) {
			if(arr[i].equals("(")) {
				stack.push(arr[i]);
			}
			else {
				if(stack.isEmpty()) {
					continue;
				}else {
					stack.pop();
					num++;
				}
			}
		}
		System.out.println("有效括号有"+num+"对");
		
	}
}