week-02. Stack-Brackets

[levi-yo]

https://www.acmicpc.net/problem/9012

[levi-yo]

import java.util.ArrayList; import java.util.Iterator; import java.util.Scanner; import java.util.Stack;

public class Bracket { static String balance(String str){ Stack s=new Stack(); String str1="YES"; for(int i=0;i<str.length();i++){ if(str.charAt(i)=='('){ s.push(str.charAt(i)); }else if(str.charAt(i)==')' && !s.isEmpty() && s.peek().equals('(')){ s.pop(); }else if(s.isEmpty() && str.charAt(i)==')'){ str1="NO"; } } if(!s.isEmpty()) str1="NO"; return str1; } public static void main(String[] args) { // TODO Auto-generated method stub ArrayList list=new ArrayList(); Scanner sc=new Scanner(System.in); int n=Integer.parseInt(sc.nextLine()); for(int i=0;i<n;i++){ String str=sc.nextLine(); list.add(balance(str)); } Iterator it=list.iterator(); while(it.hasNext()) System.out.println(it.next()); } }

[ewqsaz123]

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

public class Main { /*

• 알고리즘 분류. 스택 */ public static void main(String[] args) {

  Scanner sc = new Scanner(System.in);
  int t = sc.nextInt();
  
  ArrayList<String> arr = new ArrayList<>();
  
  for(int i=0; i<t; i++) {
      arr.add(sc.next());
  }
  
  for(int i=0; i<arr.size();i++) {
      findSolution(arr.get(i));
  }

  } public static void findSolution(String s) { Stack st = new Stack<>();

  st.push(s.charAt(0));    //첫글자는 조건없이 push
  
  for(int i=1; i<s.length();i++) {
      char c = s.charAt(i);
  
      if(c=='(') {    
          st.push(c);     //열린괄호는 스택에 push
      }else{      
          if(!st.isEmpty() && st.peek() == '(') {
              st.pop();   //'()'가 만들어지면 스택에서 pop함
          }else {
              st.push(c);
          }
  
      }
  }
  
  if(st.size() == 0) {
      System.out.println("YES");
  }else {
      System.out.println("NO");
  }

  }

}