Retrieve a pair of parenthesis with Stack.

AaaParenthesis.java

package javaapplication1.beginer;

import java.util.LinkedList;

/**
 *
 * @author naoki
 */
public class AaaParenthesis {
    public static void main(String[] args) {
        String aaa = "aaa(aaa(aa((aaa)aa))aa)a";
        LinkedList<Integer> stack = new LinkedList<>();
        for(int i = 0; i < aaa.length(); ++i){
            char ch = aaa.charAt(i);
            switch(ch){
                case 'a':
                    // do nothing
                    break;
                case '(':
                    stack.push(i);
                    break;
                case ')':
                    if(stack.isEmpty()){
                        System.out.println(")が多すぎます" + i);
                                return;
                    }
                    System.out.printf("%dと%dが対応%n", stack.pop(), i);
                    break;
            }
        }
        if(!stack.isEmpty()){
            System.out.println("(が多すぎます" + stack.pop());
        }
    }
}