Submission #208161

#	Time	Username	Problem	Language	Result	Execution time	Memory
208161		E869120	Amusement Park (CEOI19_amusementpark)	C++14	100 / 100	2606 ms	266744 KiB

amusementpark

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
#pragma warning (disable: 4996)

int mod = 998244353;
int N, M, A[1009], B[1009];
int dp[387420489], power3[19], col[19];
vector<int> X[1009];

int main() {
	cin >> N >> M;
	for (int i = 1; i <= M; i++) { cin >> A[i] >> B[i]; A[i]--; B[i]--; }
	for (int i = 1; i <= M; i++) { X[A[i]].push_back(B[i]); X[B[i]].push_back(A[i]); }
	
	power3[0] = 1;
	for (int i = 1; i <= N; i++) power3[i] = 3LL * power3[i - 1];
	for (int i = 0; i < N; i++) {
		int ret = 2 * power3[i];
		for (int j = i + 1; j < N; j++) ret += power3[j];
		for (int j : X[i]) { if (j < i) ret += power3[j]; }
		dp[ret] = 1;
	}

	for (int i = 0; i < power3[N]; i++) {
		if (dp[i] == 0) continue;

		int val = 0;
		for (int j = 0; j < N; j++) col[j] = (i / power3[j]) % 3;
		for (int j = 0; j < N; j++) {
			if (col[j] != 1) continue;
			int ret = i + power3[j] - val;
			for (int k : X[j]) { if ((col[k] == 1 && k < j) || col[k] == 0) ret += power3[k]; }
			dp[ret] += dp[i]; val += power3[j];
			if (dp[ret] >= mod) dp[ret] -= mod;
		}
	}

	long long val = dp[power3[N] - 1];
	val *= M; val %= mod;
	if (val % 2 == 1) val += mod; val /= 2LL;
	cout << val << endl;
	return 0;
}

Compilation message (stderr)

amusementpark.cpp:5:0: warning: ignoring #pragma warning  [-Wunknown-pragmas]
 #pragma warning (disable: 4996)
 
amusementpark.cpp: In function 'int main()':
amusementpark.cpp:42:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if (val % 2 == 1) val += mod; val /= 2LL;
  ^~
amusementpark.cpp:42:32: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if (val % 2 == 1) val += mod; val /= 2LL;
                                ^~~

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 21 / 21
• Subtask 5: 37 / 37