Submission #975458

#	Time	Username	Problem	Language	Result	Execution time	Memory
975458		pavement	Hidden Sequence (info1cup18_hidden)	C++17	100 / 100	13 ms	696 KiB

hidden

#include "grader.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> findSequence(int N) {
	int minority;
	if (isSubsequence(vector<int>(N / 2 + 1, 0))) {
		minority = 1;
	} else {
		minority = 0;
	}
	int len = N / 2;
	for (; len >= 0; len--) {
		if (isSubsequence(vector<int>(len, minority))) {
			break;
		}
	}
	if (len == 0) {
		return vector<int>(N, !minority);
	}
	vector<int> ret(N, minority);
	for (int i = 1; i <= N - len; i++) {
		int b = i - 1, d = (N - len) - i, lo = 0, hi = N / 2 - d, a = N;
		while (lo <= hi) {
			int cur_a = (lo + hi) / 2, cur_c = len - cur_a;
			vector<int> to_ask(cur_a + d + 1, minority);
			fill(to_ask.begin() + cur_a, to_ask.end(), !minority);
			if (isSubsequence(to_ask)) {
				a = cur_a;
				lo = cur_a + 1;
			} else {
				hi = cur_a - 1;
			}
		}
		lo = 0, hi = N / 2 - b;
		int c = N;
		while (lo <= hi) {
			int cur_c = (lo + hi) / 2, cur_a = len - cur_c;
			vector<int> to_ask(b + cur_c + 1, minority);
			fill(to_ask.begin(), to_ask.begin() + b + 1, !minority);
			if (isSubsequence(to_ask)) {
				c = cur_c;
				lo = cur_c + 1;
			} else {
				hi = cur_c - 1;
			}
		}
		int x = (a == N / 2 - d || a == N ? len - c : a);
		ret[x + i - 1] = !minority;
	}
	return ret;
}

Compilation message (stderr)

hidden.cpp: In function 'std::vector<int> findSequence(int)':
hidden.cpp:25:31: warning: unused variable 'cur_c' [-Wunused-variable]
   25 |    int cur_a = (lo + hi) / 2, cur_c = len - cur_a;
      |                               ^~~~~
hidden.cpp:38:31: warning: unused variable 'cur_a' [-Wunused-variable]
   38 |    int cur_c = (lo + hi) / 2, cur_a = len - cur_c;
      |                               ^~~~~
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