Submission #299644

#	Time	Username	Problem	Language	Result	Execution time	Memory
299644		E869120	Table Tennis (info1cup20_tabletennis)	C++14	87 / 100	73 ms	3952 KiB

tabletennis

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

int N, K;
int A[1 << 18];
bool used[1 << 18];

bool solve(int border) {
	for (int i = 0; i < N + K; i++) used[i] = false;
	
	int cl = 0, cr = N + K - 1, cnt = 0;
	while (cl < cr && cnt < (N / 2)) {
		if (A[cl] + A[cr] > border) cr--;
		else if (A[cl] + A[cr] < border) cl++;
		else {
			used[cl] = true;
			used[cr] = true;
			cl += 1;
			cr -= 1;
			cnt += 1;
		}
	}
	
	if (cnt == (N / 2)) return true;
	return false;
}

int main() {
	// Step #1. Input
	scanf("%d%d", &N, &K);
	for (int i = 0; i < N + K; i++) scanf("%d", &A[i]);
	sort(A, A + (N + K));
	
	// Step #2. BruteForce
	map<long long, int> Map;
	vector<long long> Cand, Cand2;
	for (int i = 0; i < (K + 2) * 50; i++) {
		int t1 = 1000000, t2 = 1000000;
		while (t2 < 0 || t2 >= N + K) {
			t1 = rand() % (N + K);
			t2 = (N - 1 - t1) + (rand() % (2 * K + 1));
		}
		int val = A[t1] + A[t2];
		Map[val] += 1;
		Cand2.push_back(val);
	}
	sort(Cand2.begin(), Cand2.end());
	Cand2.erase(unique(Cand2.begin(), Cand2.end()), Cand2.end());
	for (int i = 0; i < Cand2.size(); i++) {
		//cout << Cand2[i] << " " << Map[Cand2[i]] << endl;
		if (Map[Cand2[i]] >= 6) Cand.push_back(Cand2[i]);
	}
	
	// Step #3. Tansaku
	for (int i = 0; i < Cand.size(); i++) {
		bool I = solve(Cand[i]);
		if (I == false) continue;
		vector<int> vec;
		for (int j = 0; j < N + K; j++) {
			if (used[j] == true) vec.push_back(A[j]);
		}
		for (int j = 0; j < vec.size(); j++) {
			if (j) printf(" ");
			printf("%d", vec[j]);
		}
		printf("\n");
		return 0;
	}
	return 0;
}

Compilation message (stderr)

tabletennis.cpp: In function 'int main()':
tabletennis.cpp:49:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |  for (int i = 0; i < Cand2.size(); i++) {
      |                  ~~^~~~~~~~~~~~~~
tabletennis.cpp:55:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |  for (int i = 0; i < Cand.size(); i++) {
      |                  ~~^~~~~~~~~~~~~
tabletennis.cpp:62:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |   for (int j = 0; j < vec.size(); j++) {
      |                   ~~^~~~~~~~~~~~
tabletennis.cpp:30:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |  scanf("%d%d", &N, &K);
      |  ~~~~~^~~~~~~~~~~~~~~~
tabletennis.cpp:31:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   31 |  for (int i = 0; i < N + K; i++) scanf("%d", &A[i]);
      |                                  ~~~~~^~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 9 / 9
• Subtask 3: 14 / 14
• Subtask 4: 15 / 15
• Subtask 5: 9 / 9
• Subtask 6: 14 / 14
• Subtask 7: 15 / 15
• Subtask 8: 0 / 13