HDU5831 Rikka with Parenthesis II

Rikka with Parenthesis II

                                                                     Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536
K (Java/Others)

                                                                                             Total Submission(s): 1622    Accepted Submission(s): 713


Problem Description

As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them:

Correct parentheses sequences can be defined recursively as follows:

1.The empty string "" is a correct sequence.

2.If "X" and "Y" are correct sequences, then "XY" (the concatenation of X and Y) is a correct sequence.

3.If "X" is a correct sequence, then "(X)" is a correct sequence.

Each correct parentheses sequence can be derived using the above rules.

Examples of correct parentheses sequences include "", "()", "()()()", "(()())", and "(((())))".

Now Yuta has a parentheses sequence S,
and he wants Rikka to choose two different position i,j and
swap Si,Sj. 

Rikka likes correct parentheses sequence. So she wants to know if she can change S to a correct parentheses sequence after this operation.

It is too difficult for Rikka. Can you help her?

 

Input

The first line contains a number t(1<=t<=1000), the number of the testcases. And there are no more then 10 testcases with n>100

For each testcase, the first line contains an integers n(1<=n<=100000), the length of S. And the second line contains a string of length S which only contains ‘(’ and ‘)’.

 

Output

For each testcase, print "Yes" or "No" in a line.

 

Sample Input

3
4
())(
4
()()
6
)))(((

 

Sample Output

Yes
Yes
No

Hint
For the second sample input, Rikka can choose (1,3) or (2,4) to swap. But do nothing is not allowed.

 ————————————————————————————————

问给一个（）的序列，问交换两个之后是否合法

思路：先判数量是否一样，记录（的数量，遇到的第一个）可以当做（，注意（）的情况

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <vector>
#include <bitset>
#include <functional>

using namespace std;

#define LL long long
const int INF = 0x3f3f3f3f;

int n;
char ch[100009];

int main()
{
int t;
scanf("%d",&t);
while(t--)
{
scanf("%d%s",&n,ch);
int sum1=0,sum2=0;
for(int i=0;ch[i];i++)
{
if(ch[i]=='(') sum1++;
else sum2++;
}
if(sum1!=sum2) {printf("No\n");continue;}
if(n==2&&!strcmp(ch,"()")) {printf("No\n");continue;}
int flag=0,fl=0,sum=0;
for(int i=0;i<n;i++)
{
if(ch[i]=='(') sum++;
else
{
if(sum) {sum--;continue;}

if(fl==0) fl=1,sum++;
else {flag=1;break;}

}
}
if(flag!=1) printf("Yes\n");
else printf("No\n");
}
return 0;
}