括号匹配 Java Sample

check_brackets.java

import java.util.*;

public class Main{
  public static boolean checkLegal(String A) {
    Stack<Character> s = new Stack<>();
    HashMap<Character,Character> map = new HashMap<Character,Character>();
    map.put('[',']');
    map.put('{','}');
    map.put('(',')');
    for (char c : A.toCharArray()) {
      if (map.containsKey(c)) {
        s.push(c);
      }else if(map.containsValue(c)){
        if(s.isEmpty())
          return false;
       char top = s.peek();
        if(map.get(top).equals(c){
          s.pop();
        } else {
          return false;
        }
      }
    }
    return s.isEmpty();
  }
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