CF1227C Messy

思路：

构造题。首先把字符串变成“(((((...)))))”的样子，再根据k的取值变成“()()()...((...))”的样子即可。

实现：

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int T; cin >> T;
 6     while (T--)
 7     {
 8         int n, k; string s; cin >> n >> k >> s;
 9         vector<pair<int, int>> res;
10         for (int i = 0; i < n / 2; i++)
11         {
12             if (s[i] == '(') continue;
13             int j = i + 1;
14             while (j < n && s[j] != '(') j++;
15             res.push_back(make_pair(i, j));
16             reverse(s.begin() + i, s.begin() + j + 1);
17         }
18         for (int i = 0; i < k - 1; i++)
19         {
20             int cur = 2 * i + 1;
21             int j = cur + 1;
22             while (j < n && s[j] != ')') j++;
23             res.push_back(make_pair(cur, j));
24             reverse(s.begin() + cur, s.begin() + j + 1);
25         }
26         cout << res.size() << endl;
27         for (auto it: res)
28         {
29             cout << it.first + 1 << " " << it.second + 1 << endl;
30         }
31     }
32     return 0;
33 }