Submission #674341

#	Time	Username	Problem	Language	Result	Execution time	Memory
674341		QwertyPi	Hidden Sequence (info1cup18_hidden)	C++14	100 / 100	390 ms	364 KiB

hidden

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int, int>

#ifndef TEST
#include "grader.h"
#endif

using namespace std;

vector<int> a;
#ifdef TEST
bool isSubsequence(vector<int> S){
	cout << "QRY "; for(auto i : S) cout << i << ' '; 
	int l = 0, r = 0;
	while(l < a.size() && r < S.size()){
		if(a[l] != S[r]) l++;
		else l++, r++;
	}
	cout << (r == S.size() ? "YES" : "NO") << endl;
	return r == S.size();
}
#else
bool isSubsequence(vector<int> S);
#endif

bool flipped = false;
bool iss(vector<int>& S){
	if(flipped) for(auto& i : S) i = 1 - i;
	return isSubsequence(S);
}

int dp[201][201];
int N, c0, c1;

int f(int i, int j){
	if(dp[i][j] != -1) return dp[i][j];
	return N / 2 + 1 - (c0 - (j - i));
}
vector<int> findSequence(int N){ ::N = N;
	c0 = 0, c1 = 0;
	for(int i = 1; i <= N / 2 + 1; i++){
		vector<int> a; for(int j = 0; j < i; j++) a.push_back(0);
		if(!isSubsequence(a)){
			c0 = i - 1, c1 = N - (i - 1);
			break;
		}
	}
	for(int i = 1; i <= N / 2 + 1; i++){
		vector<int> a; for(int j = 0; j < i; j++) a.push_back(1);
		if(!isSubsequence(a)){
			c0 = N - (i - 1), c1 = i - 1;
			break;
		}
	}
	if(c0 >= c1) flipped = true, swap(c0, c1);

	for(int l = 0; l <= c0; l++){
		for(int r = 0; r <= c0; r++){
			if(l - 1 < r) dp[l][r] = -1;
			else if(l - 1 > r) dp[l][r] = -2;
			else dp[l][r] = 0;
		}
	}
	for(int l = 0; l <= c0; l++){
		for(int r = l; r <= c0; r++){
			int d = r - l;
			int quota = (N / 2 + 1) - (c0 - d);
			int ll = l == r ? 0 : max(dp[l][r - 1], dp[l + 1][r]), rr = quota;
			while(ll != rr){
				vector<int> qry;
				for(int j = 0; j < l; j++){
					qry.push_back(0);
				}
				for(int j = 1; j <= (ll + rr + 1) / 2; j++){
					qry.push_back(1);
				}
				for(int j = r; j < c0; j++){
					qry.push_back(0);
				}
				if(iss(qry)){
					ll = (ll + rr + 1) / 2;
				}else{
					rr = (ll + rr + 1) / 2 - 1;
				}
			}
			dp[l][r] = (ll == quota ? -1 : ll);
		}
	}
	dp[0][c0] = c1;
	for(int tr = 0; tr <= c0; tr++){
		for(int d = c0 - 1; d >= 0; d--){
			for(int i = 0; i < c0 - d; i++){
				for(int j = i + d; j <= i + d; j++){
					if(dp[i][i] != -1 && dp[i][j + 1] != -1) dp[i + 1][j + 1] = dp[i][j + 1] - dp[i][i];
					if(dp[j + 1][j + 1] != -1 && dp[i][j + 1] != -1) dp[i][j] = dp[i][j + 1] - dp[j + 1][j + 1];
					if(dp[i][j] == -1 && dp[i + 1][j] != -1 && dp[i][j + 1] != -1 && dp[i + 1][j + 1] != -1)
						dp[i][j] = dp[i + 1][j] + dp[i][j + 1] - dp[i + 1][j + 1];
					
					if(dp[i][j] != -1 && dp[i + 1][j] == -1 && dp[i][j + 1] != -1 && dp[i + 1][j + 1] != -1)
						dp[i + 1][j] = dp[i][j] - dp[i][j + 1] + dp[i + 1][j + 1];
					
					if(dp[i][j] != -1 && dp[i + 1][j] != -1 && dp[i][j + 1] == -1 && dp[i + 1][j + 1] != -1)
						dp[i][j + 1] = dp[i][j] - dp[i + 1][j] + dp[i + 1][j + 1];
					
					if(dp[i][j] != -1 && dp[i + 1][j] != -1 && dp[i][j + 1] != -1 && dp[i + 1][j + 1] == -1)
						dp[i + 1][j + 1] = dp[i + 1][j] + dp[i][j + 1] - dp[i][j];
				}
			}
		}
	}

	vector<int> ans;
	int tot = 0, s = 0;
	for(int i = 0; i <= c0; i++){
		tot += dp[i][i] < 0 ? 0 : dp[i][i];
		s += dp[i][i] < 0;
	}
	
	for(int i = 0; i <= c0; i++){
		if(dp[i][i] == -1){ dp[i][i] = (c1 - tot) / s; }
	}
	
	for(int i = 0; i <= c0; i++){
		for(int j = 0; j < dp[i][i]; j++) ans.push_back(1);
		if(i != c0) ans.push_back(0);
	}
	
	if(flipped){
		for(auto& i : ans) i = 1 - i;
	}
	return ans;
}

#ifdef TEST
int main(){
	int n; cin >> n;
	vector<int> a;
	for(int i = 0; i < n; i++){
		int v; cin >> v; a.push_back(v);
	}
	::a = a;
	vector<int> ans = findSequence(n);
	for(auto i : ans) cout << i << ' '; cout << endl;
}
#endif

Compilation message (stderr)

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: 80 / 80