hdu_5831_Rikka with Parenthesis II(模拟)

题目链接：hdu_5831_Rikka with Parenthesis II

题意：

给你一些括号的排列，必须交换一次，能不能将全部的括号匹配

题解：

模拟一下括号的匹配就行了，注意要特判只有一对括号是NO，因为必须要交换一次

#include <cstdio>
#include <cstring>
const int N = 1e5 +5;
char s[N];
int st[N],top;
int main()
{
    int t;
    scanf("%d", &t);
    while (t--)
    {
        int n;
        scanf("%d", &n);
        scanf("%s", s);
        if (n == 2 && s[0] == '(' && s[1] == ')') {printf("No
"); continue;}
        top = 0; st[0] = -1;
        for (int i = 0; i < n; i++)
        {
            if (s[i] == '(') st[++top] = 0;
            else if (st[top] == 0) top--;
            else st[++top] = 1;
        }
        if (top == 0) printf("Yes
");
        else if (top == 2 && st[1] == 1 && st[2] == 0) printf("Yes
");
        else if (top == 4 && st[1] == 1 && st[2] == 1 && st[3] == 0 && st[4] == 0) printf("Yes
");
        else printf("No
");
    }
    return 0;
}