左右符號對稱問題

寫一個介面

package stack;

public interface Stack<E> {
    int size();
    boolean isEmpty();
    void push(E e);

    E top();
    E pop();
}

實作Stack Push Pop 方法

package stack;

public class ArrayStack<E> implements Stack<E>{
    public static int CAPACITY = 100;
    private E[] data;
    private int t = -1;
    public  ArrayStack(){ this(CAPACITY);}

    public ArrayStack(int capacity) {
        data = (E[]) new Object[capacity];
    }

    @Override
    public int size() {
        return t+1;
    }

    @Override
    public boolean isEmpty() {
        return t==-1;
    }

    @Override
    public void push(E e) {
        if(size()==data.length)  throw  new IllegalStateException("Stack is full");
        data[++t] = e;
    }

    @Override
    public E top() {
        if(isEmpty()) return null;
        return data[t];
    }

    @Override
    public E pop() {
        if (isEmpty()) return null;
        E answer = data[t];
        data[t] = null;
        t--;
        return answer;
    }
}

寫一個Delimiter 物件

public class Delimiter {
    char c;
    int pos;
    public Delimiter(char c, int pos){
        this.c = c;
        this.pos = pos;
    }
}

package stack;

import java.util.Scanner;

public class MatchDelimiter {
    static String str ;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Delimiter d;
//        str = "((a+b)*(c+d))";
//        str ="((a+b)*(c+d()";
//        str = "(4*5+6*(7+8)/2-(4*3)-2)*3";
        str = "((a+b)-c*e)+(e*(f-g)";
        Stack<Delimiter> buf = new ArrayStack<>();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            switch (ch){
                case '(': buf.push(new Delimiter('(',i)); break;
                case ')':
                    if (!buf.isEmpty()){
                        d = buf.pop();
                        if (d.c=='('){
                            System.out.println(d.pos+","+i);
                        }
                    }
                    break;
            }
        }
        while (!buf.isEmpty()){
            d = buf.pop();
            System.out.println(d.pos+",-1");
        }
    }
}