题解 | #有效括号序列#

import java.util.*;


public class Solution {
  /**
   *
   * @param s string字符串
   * @return bool布尔型
   */
  public boolean isValid (String s) {
    Stack<Character> stack = new Stack<>();
    for (int i = 0; i < s.length(); i++) {
      if(!stack.isEmpty()&&(stack.peek()=='('&&s.charAt(i)==')' || stack.peek()=='['&&s.charAt(i)==']' || stack.peek()=='{'&&s.charAt(i)=='}' ))
        stack.pop();
      else
        stack.push(s.charAt(i));
    }
    return stack.isEmpty();
  }
}