Submission #475003

# Submission time Handle Problem Language Result Execution time Memory
475003 2021-09-20T12:25:15 Z hhhhaura Cat (info1cup19_cat) C++14
25 / 100
662 ms 27404 KB
#define wiwihorz
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma loop-opt(on)

#define rep(i, a, b) for(int i = a; i <= b; i ++)
#define rrep(i, a, b) for(int i = b; i >= a; i--)
#define all(x) x.begin(), x.end()
#define ceil(a, b) ((a + b - 1) / (b))

using namespace std;

#define int long long int
#define lld long double
#define pii pair<int, int>
#define random mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count())

#ifdef wiwihorz
#define print(a...) cerr << "Line: " << __LINE__, kout("[" + string(#a) + "] = ", a)
void vprint(auto L, auto R) { while(L < R)cerr << *L << " \n"[next(L) == R], ++L; }
void kout() { cerr << endl; }
template<class T1, class ... T2> void kout(T1 a, T2 ... e) { cerr << a << " ", kout(e...);}
#else
#define print(...) 0
#define vprint(...) 0
#endif
namespace solver {
	int n;
	vector<int> a, b, vis, top, inv;
	vector<pii> ans;
	void init_(int _n) {
		n = _n;
		a.assign(n + 1, 0);
		b.assign(n + 1, 0);
		vis.assign(n + 1, -1);
		top.assign(n + 1, 0);
		inv.assign(n + 1, 0);
		ans.clear();
	}
	void dfs(int x) {
		vis[x] = 0;
		if(!b[x]) {
			if(vis[a[x]] == -1) dfs(a[x]);
			top[x] = top[a[x]], top[a[x]] = 0;
		}
		else top[x] = x;
	}
	void solve() {
		int cnt = 0;
		rep(i, 1, n / 2) {
			if(a[i] + a[n - i + 1] != n + 1) {
				cout << "-1\n";
				return;
			}
			if(a[i] > n / 2) {
				b[i] = 1, cnt++;
				swap(a[i], a[n - i + 1]);
			}
		}
		if(cnt & 1) {
			cout << "-1\n";
			return;
		}
		rep(i, 1, n / 2) {
			inv[a[i]] = i;
			if(vis[i] == -1) dfs(i);
		}
		rep(i, 1, n / 2) if(top[i] && b[top[i]]) {
//			print(i, top[i]);
			if(a[top[i]] != i && b[inv[i]]) {
				b[top[i]] = 0, b[inv[i]] = 0;
				ans.push_back({top[i], n - inv[i] + 1});
				swap(a[top[i]], a[inv[i]]);
				swap(a[n - top[i] + 1], a[n - inv[i] + 1]);
			}
		}
		vector<int> temp;
		rep(i, 1, n / 2) if(b[i]) {
			assert(top[a[i]] == i);
			temp.push_back(i);
		}
//		print(temp.size());
//		vprint(all(temp));
		assert(temp.size() % 2 == 0);
		for(int i = 0; i < temp.size(); i += 2) {
			int x = temp[i], y = temp[i + 1];
			ans.push_back({x, n - y + 1});
			swap(a[x], a[y]);
			swap(a[n - x + 1], a[n - y + 1]);
		}
		rep(i, 1, n / 2) if(a[i] != i && !vis[i]){
			int cur = a[i];
			temp.clear(), temp.push_back(i);
			vis[i] = 1;
			while(cur != i) {
				temp.push_back(cur);
				vis[cur] = 1;
				cur = a[cur];
			}
			rrep(j, 0, signed(temp.size()) - 2) {
				ans.push_back({temp[j], temp[j + 1]});
			}
		}
		cout << ans.size() << " " << ans.size() << "\n";
		for(auto i : ans) cout << i.first << " " << i.second << "\n";
	}
};
using namespace solver;
signed main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int t; cin >> t;
	while(t--) {
		int n; cin >> n;
		init_(n);
		rep(i, 1, n) cin >> a[i];
		solve();
	}
	return 0;
}

Compilation message

cat.cpp:4: warning: ignoring '#pragma loop ' [-Wunknown-pragmas]
    4 | #pragma loop-opt(on)
      | 
cat.cpp:20:13: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   20 | void vprint(auto L, auto R) { while(L < R)cerr << *L << " \n"[next(L) == R], ++L; }
      |             ^~~~
cat.cpp:20:21: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   20 | void vprint(auto L, auto R) { while(L < R)cerr << *L << " \n"[next(L) == R], ++L; }
      |                     ^~~~
cat.cpp: In function 'void solver::solve()':
cat.cpp:85:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |   for(int i = 0; i < temp.size(); i += 2) {
      |                  ~~^~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Runtime error 1 ms 460 KB Execution killed with signal 6
# Verdict Execution time Memory Grader output
1 Correct 36 ms 932 KB Output is correct
2 Correct 28 ms 1020 KB Output is correct
# Verdict Execution time Memory Grader output
1 Runtime error 1 ms 460 KB Execution killed with signal 6
# Verdict Execution time Memory Grader output
1 Correct 36 ms 932 KB Output is correct
2 Correct 28 ms 1020 KB Output is correct
3 Correct 658 ms 21496 KB Output is correct
4 Correct 599 ms 21672 KB Output is correct
5 Correct 662 ms 27404 KB Output is correct
# Verdict Execution time Memory Grader output
1 Runtime error 1 ms 460 KB Execution killed with signal 6