【数组元素交换，观察法】B. Reverse Sort

题目来源

Problem - B - CodeforcesCodeforces. Programming competitions and contests, programming communityhttps://codeforces.com/contest/1605/problem/B

题干

 

解释

通过一些观察，发现在一步之内总能将数组元素交换成目标数组的顺序

因此只需要将原数组与排好序的数组进行一次对比，然后将不相同的元素做好标记再交换就可以啦

代码段

void solve()
{
	int n; cin >> n;
	string s; cin >> s;
	if (is_sorted(s.begin(), s.begin() + n))
	{
		cout << 0 << endl;
		return;
	}
	string t = s;
	sort(t.begin(), t.end());
	cout << 1 << endl;
	vector<int>ans;
	for (int i = 0; i < n; i++)
	{
		if (s[i] != t[i])
			ans.push_back(i + 1);
	}
	cout << ans.size() << ' ';
	for (int i = 0; i < ans.size(); i++)cout << ans[i] << ' ';
	cout << endl;
}