hdu2刷水题 练习 c++模板

括号配对问题
import java.io.*;
import java.util.*;
public class MainNo2 {
 public static void main(String args[]) throws Exception {
  Scanner cin = new Scanner(System.in);
  Stack<Character> st;
  int n = cin.nextInt();
  while (n != 0) {
   String s = cin.next();
   if (s.length() % 2 == 1)
    System.out.println("No");
   else {
    st = new Stack<Character>();
    for (int j = 0; j < s.length(); j++) {
     char tmp = s.charAt(j);
     if (tmp == '(' || tmp == '[')
      st.push(tmp);
     else {
      char ct = st.peek();
      if ((tmp == ')' && ct == '(')
        || (tmp == ']' && ct == '[')) {
       st.pop();
       continue;
      } else {
       break;
      }
     }
     if (st.isEmpty())
      break;
    }
    if (st.isEmpty())
     System.out.println("Yes");
    else
     System.out.println("No");
   }
   n--;
  }
 }
}
我这代码就是不能过，总是提示RuntimeError错误
后改为如下：
import java.util.Scanner;
import java.util.Stack;

public class Main12 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        Stack<Character> stack;
        while(n != 0)
        {
            String s = scan.next();
            if(s.length() % 2 == 1)
                System.out.println("No");
            else
            {
                stack = new Stack<Character>();
                for(int i = 0;i < s.length();i++)
                {
                    if(stack.isEmpty())
                        stack.push(s.charAt(i));
                    else if((stack.peek() == '[' && s.charAt(i) == ']')
                            || (stack.peek() == '(' && s.charAt(i) == ')'))
                        stack.pop();
                    else
                        stack.push(s.charAt(i));
                }
                if(stack.isEmpty())
                    System.out.println("Yes");
                else
                    System.out.println("No");
            }
            n--;
        }
    }
}

 就好了。

仍然没有发现问题出在哪里。。

查看内存及时间要求为：时间限制：3000 ms  |  内存限制：65535 KB

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Accepted

128

477

java

04-03 11:46:22

#include<iostream>
#include<vector>
#include<string>
using namespace std;
int main()
{
int n;
cin>>n;
while(n--)
{
vector<char> vec;
string ch;
vec.push_back(' ');
cin>>ch;
for(int i=0;i<ch.length();i++)
{
vec.push_back(ch[i]);
   if( vec.back()-1 == *(vec.end()-2) || vec.back()-2 == *(vec.end()-2))
{
vec.pop_back();
vec.pop_back();
}
}
if(vec.size()==1)
cout<<"Yes"<<endl;
else
cout<<"No"<<endl;
}
return 0;
}
 刷这个水题，是为了看c++模板，另外两名队友都是c++