Submission #317556

#	Time	Username	Problem	Language	Result	Execution time	Memory
317556		Kevin_Zhang_TW	Hidden Sequence (info1cup18_hidden)	C++17	20 / 100	463 ms	7800 KiB

hidden

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#define pb emplace_back
#define AI(i) begin(i), end(i)
using namespace std;
using ll = long long;
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] : ", args)
void kout() { cerr << endl; }
template<class T, class ...U>
void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
void debug(auto L, auto R) { while (L != R) cerr << *L << " \n"[next(L) == R], ++L; }
vector<int> ans{0,1,0,0,0,0,0,0,0,1,1};
int mxq;
bool isSubsequence(vector<int> a) {
	for (int i = 0, j = 0;i < a.size();++i) {
		while (j < ans.size() && ans[j] != a[i])
			++j;
		if (j == ans.size()) return false;
		++j;
	}
	mxq = max(mxq, (int)a.size());
	
	return true;
}
#else
#include "grader.h"
#define debug(...) 0
#define DE(...) 0
#endif
const int MAX_N = 300010, inf = 1e9;
const vector<int> zero{0}, one{1};
int n;
bool query(vector<int> a) {
	if (a.size() > n) return false;
	return isSubsequence(a);
}

vector<int> operator + (vector<int> a, vector<int> b) {
	a.insert(end(a), AI(b));
	return a;
}
vector<pair<int,int>> edge[MAX_N];
int dp[MAX_N];

vector<int> findSequence(int _n) {
	n = _n;
	int flip = 0;
	auto makev = [&](int a, int v1, int b, int v2, int c, int v3) {
		return vector<int>(a, v1^flip) + vector<int>(b, v2^flip) + vector<int>(c, v3^flip);
	};
	auto con = [&](int l, int r, int sum) {
		DE(l, r, sum);
		edge[r].pb(l-1, -sum);
	};
	auto concon = [&](int l, int r, int sum) {
		edge[l-1].pb(r, sum);
	};
	DE(n);

	vector<int> Z, O, ans;

	while (Z.size() == O.size() && Z.size() + O.size() < n) {

		if (query(Z + zero))
			Z.pb(0);

		if (query(O + one))
			O.pb(1);

	}

	if (Z.size() > O.size())
		swap(Z, O), flip ^= 1;

	while (Z.size () + O.size () < n)
		O.pb(0);


	int m = Z.size();

	//con(1, m+1, O.size());

	auto bellmand = [&]() {
		dp[m+1] = O.size();
		fill(dp+1, dp+m+1, inf);
		//queue<info> q;
		//queue<pair<int,int>> q;
		//q.emplace(m+1, dp[m+1]);

		//q.emplace(0, 0);
		queue<int> q;
		vector<bool> inq(m+2);
		auto mpush = [&](int x) {
			if (inq[x]) return;
			inq[x] = true;
			q.emplace(x);
		};

		mpush(0), mpush(m+1);
		while (q.size()) {
			int x = q.front(); q.pop();
			inq[x] = false;
			for (auto [u, w] : edge[x]) 
				if (dp[x] + w < dp[u]) {
					dp[u] = dp[x] + w;
					mpush(u);
				}
		}
	};

	//const int lim = (n * 3 + 3) / 4;
	const int lim = ((n) / 2) + 1;


	for (int l0 = 0;l0 <= m;++l0)
		for (int r0 = 0;r0 + l0 <= m;++r0) {
			int mx1 = 0;
			int l = 0, r = lim - l0 - r0, mid;

			while (l < r) {
				mid = l + r >> 1; 
				if (query(makev(l0, 0, mid+1, 1, r0, 0)))
					l = mid+1;
				else
					r = mid;
			}

			mx1 = l;
			DE(mx1);

			assert(query(makev(l0, 0, l, 1, r0, 0)));

			con(l0+1, m+1 - r0, mx1);
			if (l0 + r0 + mx1 < lim)
				concon(l0+1, m+1 - r0, mx1);
		}

	bellmand();

	for (int i = m+1;i >= 1;--i)
		dp[i] -= dp[i-1];
	for (int i = 1;i <= m+1;++i) {
		while (dp[i]--)
			ans.pb( 1 ^ flip );
		if (i <= m)
			ans.pb( 0 ^ flip );
	}
	return ans;

}
#ifdef KEV
int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	vector<int> res = findSequence(ans.size());
	if (res == ans) {
		cerr << "AC!\n";
		DE(mxq);
	}
	else {
		cerr << "WA\n";
		debug(AI(res));
		cerr << "Should be\n";
		debug(AI(ans));
	}
}
#endif

Compilation message (stderr)

hidden.cpp: In function 'bool query(std::vector<int>)':
hidden.cpp:35:15: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   35 |  if (a.size() > n) return false;
      |      ~~~~~~~~~^~~
hidden.cpp: In lambda function:
hidden.cpp:29:17: warning: statement has no effect [-Wunused-value]
   29 | #define DE(...) 0
      |                 ^
hidden.cpp:53:3: note: in expansion of macro 'DE'
   53 |   DE(l, r, sum);
      |   ^~
hidden.cpp: In function 'std::vector<int> findSequence(int)':
hidden.cpp:29:17: warning: statement has no effect [-Wunused-value]
   29 | #define DE(...) 0
      |                 ^
hidden.cpp:59:2: note: in expansion of macro 'DE'
   59 |  DE(n);
      |  ^~
hidden.cpp:63:53: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   63 |  while (Z.size() == O.size() && Z.size() + O.size() < n) {
      |                                 ~~~~~~~~~~~~~~~~~~~~^~~
hidden.cpp:76:31: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   76 |  while (Z.size () + O.size () < n)
      |         ~~~~~~~~~~~~~~~~~~~~~~^~~
hidden.cpp:122:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  122 |     mid = l + r >> 1;
      |           ~~^~~
hidden.cpp:29:17: warning: statement has no effect [-Wunused-value]
   29 | #define DE(...) 0
      |                 ^
hidden.cpp:130:4: note: in expansion of macro 'DE'
  130 |    DE(mx1);
      |    ^~
grader.cpp: In function 'int main()':
grader.cpp:28:26: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wformat=]
   28 |     fprintf (fifo_out, "%d\n", ans.size ());
      |                         ~^     ~~~~~~~~~~~
      |                          |              |
      |                          int            std::vector<int>::size_type {aka long unsigned int}
      |                         %ld
grader.cpp:29:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     for (int i=0; i<ans.size () && i < N; i++)
      |                   ~^~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80