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Submission #401227

# Submission time Handle Problem Language Result Execution time Memory
401227 2021-05-09T16:24:30 Z galca A Difficult(y) Choice (BOI21_books) C++14
10 / 100
 3 ms 968 KB 
#include <iostream>
#include <vector>
#include <set>
using namespace std;

#include "books.h"

int findA(vector<long long>& books, long long A, int lower, int upper) {
	if (books[lower] == -1) {
		books[lower] = skim(lower + 1);
	}
	if (books[upper] == -1) {
		books[upper] = skim(upper + 1);
	}
	if (books[lower] > A) {
		return -1;
	}
	if (books[upper] <= A) {
		return upper;
	}

	if (upper - lower < 2) {
		return lower;
	}

	int half = (upper - lower + 1) / 2;
	books[lower + half] = skim(lower + half + 1);

	if (books[lower + half] <= A) return findA(books, A, lower + half, upper);
	else return findA(books, A, lower, lower + half);
}

void solve(int N, int K, long long A, int S) {
	if (K > N) {
		impossible();
		return;
	}
	vector<long long> books(N);

	for (int i = 0; i < N; i++) {
		books[i] = -1;
	}

	long long sumFirstK = 0;
	for (int i = 0; i < K; i++) {
		if (books[i] == -1) {
			books[i] = skim(i + 1);
		}
		sumFirstK += books[i];
	}

	if (sumFirstK > A * 2) {
		impossible();
	}
	else {
		vector<int> res;
		for (int i = 0; i < K; i++) {
			res.push_back(i + 1);
		}
		if (sumFirstK >= A) {
			answer(res);
		}
		else {
			// sumFirstK < A
			// find last element < A
			long long posA = findA(books, A, 0, N - 1);
			long long currentSum = sumFirstK;
			// try to replace smallest with largest
			for (int i = 0; i < K; i++) {
				if (books[posA - i] == -1) {
					books[posA - i] = skim(posA - i + 1);
				}
				currentSum -= books[i];
				res[i] = posA - i + 1;
				currentSum += books[posA - i];
				if (currentSum >= A) {
					// check that no book appears twice
					set<int> validator;
					for (int j = 0; j < K; j++) {
						validator.insert(res[j]);
					}
					if (validator.size() == K) {
						answer(res);
					}
					else {
						impossible();
					}
					break;
				}
			}
			// failed to build the sum with elements < A only
			// need to look at elements > A

			int i = 0;
			while ((i < K) && ((posA + 1 + i) < N)) {
				if (books[posA + i + 1] == -1) {
					books[posA + i + 1] = skim(posA + i + 2);
				}
				sumFirstK -= books[K - i - 1];
				res[K - i - 1] = posA + i + 2;
				sumFirstK += books[posA + i + 1];
				if (sumFirstK > A * 2) {
					impossible();
					break;
				}
				else {
					if (sumFirstK >= A) {
						set<int> validator;
						for (int j = 0; j < K; j++) {
							validator.insert(res[j]);
						}
						if (validator.size() == K) {
							answer(res);
						}
						else {
							impossible();
						}
						break;
					}
				}
			}
			impossible();
		}
	}
	return;
}

Compilation message

books.cpp: In function 'void solve(int, int, long long int, int)':
books.cpp:82:27: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   82 |      if (validator.size() == K) {
      |          ~~~~~~~~~~~~~~~~~^~~~
books.cpp:112:28: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  112 |       if (validator.size() == K) {
      |           ~~~~~~~~~~~~~~~~~^~~~

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 328 KB Output is correct
2 Correct 1 ms 200 KB Output is correct
3 Correct 1 ms 200 KB Output is correct
4 Correct 1 ms 200 KB Output is correct
5 Correct 1 ms 200 KB Output is correct
6 Incorrect 1 ms 200 KB Incorrect
7 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 200 KB Output is correct
2 Correct 1 ms 200 KB Output is correct
3 Correct 1 ms 200 KB Output is correct
4 Correct 1 ms 200 KB Output is correct
5 Correct 1 ms 200 KB Output is correct
6 Incorrect 1 ms 200 KB Incorrect
7 Halted 0 ms 0 KB -

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 968 KB Output is correct
2 Correct 1 ms 968 KB Output is correct
3 Correct 2 ms 968 KB Output is correct
4 Correct 2 ms 968 KB Output is correct
5 Correct 1 ms 968 KB Output is correct
6 Correct 1 ms 968 KB Output is correct
7 Correct 1 ms 968 KB Output is correct
8 Correct 2 ms 968 KB Output is correct
9 Correct 1 ms 968 KB Output is correct

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 968 KB Output is correct
2 Correct 1 ms 968 KB Output is correct
3 Correct 2 ms 968 KB Output is correct
4 Correct 2 ms 968 KB Output is correct
5 Correct 1 ms 968 KB Output is correct
6 Correct 1 ms 968 KB Output is correct
7 Correct 1 ms 968 KB Output is correct
8 Correct 2 ms 968 KB Output is correct
9 Correct 1 ms 968 KB Output is correct
10 Correct 2 ms 968 KB Output is correct
11 Correct 2 ms 968 KB Output is correct
12 Correct 2 ms 968 KB Output is correct
13 Correct 2 ms 968 KB Output is correct
14 Correct 1 ms 968 KB Output is correct
15 Correct 2 ms 968 KB Output is correct
16 Correct 1 ms 968 KB Output is correct
17 Correct 2 ms 968 KB Output is correct
18 Correct 1 ms 968 KB Output is correct
19 Correct 2 ms 968 KB Output is correct
20 Correct 1 ms 968 KB Output is correct
21 Correct 1 ms 968 KB Output is correct
22 Correct 1 ms 968 KB Output is correct
23 Incorrect 2 ms 968 KB Incorrect
24 Halted 0 ms 0 KB -

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 968 KB Output is correct
2 Correct 1 ms 968 KB Output is correct
3 Correct 2 ms 968 KB Output is correct
4 Correct 2 ms 968 KB Output is correct
5 Correct 1 ms 968 KB Output is correct
6 Correct 1 ms 968 KB Output is correct
7 Correct 1 ms 968 KB Output is correct
8 Correct 2 ms 968 KB Output is correct
9 Correct 1 ms 968 KB Output is correct
10 Correct 2 ms 968 KB Output is correct
11 Correct 2 ms 968 KB Output is correct
12 Correct 2 ms 968 KB Output is correct
13 Correct 2 ms 968 KB Output is correct
14 Correct 1 ms 968 KB Output is correct
15 Correct 2 ms 968 KB Output is correct
16 Correct 1 ms 968 KB Output is correct
17 Correct 2 ms 968 KB Output is correct
18 Correct 1 ms 968 KB Output is correct
19 Correct 2 ms 968 KB Output is correct
20 Correct 1 ms 968 KB Output is correct
21 Correct 1 ms 968 KB Output is correct
22 Correct 1 ms 968 KB Output is correct
23 Incorrect 2 ms 968 KB Incorrect
24 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 968 KB Output is correct
2 Correct 1 ms 968 KB Output is correct
3 Correct 2 ms 968 KB Output is correct
4 Correct 2 ms 968 KB Output is correct
5 Correct 1 ms 968 KB Output is correct
6 Correct 1 ms 968 KB Output is correct
7 Correct 1 ms 968 KB Output is correct
8 Correct 2 ms 968 KB Output is correct
9 Correct 1 ms 968 KB Output is correct
10 Correct 2 ms 968 KB Output is correct
11 Correct 2 ms 968 KB Output is correct
12 Correct 2 ms 968 KB Output is correct
13 Correct 2 ms 968 KB Output is correct
14 Correct 1 ms 968 KB Output is correct
15 Correct 2 ms 968 KB Output is correct
16 Correct 1 ms 968 KB Output is correct
17 Correct 2 ms 968 KB Output is correct
18 Correct 1 ms 968 KB Output is correct
19 Correct 2 ms 968 KB Output is correct
20 Correct 1 ms 968 KB Output is correct
21 Correct 1 ms 968 KB Output is correct
22 Correct 1 ms 968 KB Output is correct
23 Incorrect 2 ms 968 KB Incorrect
24 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 968 KB Output is correct
2 Correct 1 ms 968 KB Output is correct
3 Correct 2 ms 968 KB Output is correct
4 Correct 2 ms 968 KB Output is correct
5 Correct 1 ms 968 KB Output is correct
6 Correct 1 ms 968 KB Output is correct
7 Correct 1 ms 968 KB Output is correct
8 Correct 2 ms 968 KB Output is correct
9 Correct 1 ms 968 KB Output is correct
10 Correct 2 ms 968 KB Output is correct
11 Correct 2 ms 968 KB Output is correct
12 Correct 2 ms 968 KB Output is correct
13 Correct 2 ms 968 KB Output is correct
14 Correct 1 ms 968 KB Output is correct
15 Correct 2 ms 968 KB Output is correct
16 Correct 1 ms 968 KB Output is correct
17 Correct 2 ms 968 KB Output is correct
18 Correct 1 ms 968 KB Output is correct
19 Correct 2 ms 968 KB Output is correct
20 Correct 1 ms 968 KB Output is correct
21 Correct 1 ms 968 KB Output is correct
22 Correct 1 ms 968 KB Output is correct
23 Incorrect 2 ms 968 KB Incorrect
24 Halted 0 ms 0 KB -