括号匹配

import java.util.Scanner;
import java.util.Stack;

public class Test15 {

    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){  
            String str = sc.nextLine();
            Stack<Character> s = new Stack<Character>();
            if(str.length() % 2 != 0){  
                System.out.println(str+" -> "+"FALSE");  
            }else{ 
                boolean flag = true;
                for (int i = 0; i < str.length(); i++) {
                    char ch = str.charAt(i);
                    if(ch=='('||ch=='['||ch=='{'){
                        switch(ch){
                        case '(': s.push(')');break;
                        case '[': s.push(']');break;
                        case '{': s.push('}');break;
                        }
                    }
                    else if(ch==')'||ch==']'||ch=='}'){
                        if(s.isEmpty()||ch!=s.peek()){
                            flag = false;
                            System.out.println(str+" -> "+"FALSE");
                            break;
                        }else{
                            s.pop();
                        }
                    }
                }
                if(s.isEmpty())
                    System.out.println(str+" -> "+"TRUE");
                else if(flag)
                    System.out.println(str+" -> "+"FALSE");
            }
            
      }
    }
        
}

/*
 ()
 [()]
 ()()
 ({}([]))
 )
 ({
 {)(}
 
 
 */