Submission #579554

#	Time	Username	Problem	Language	Result	Execution time	Memory
579554		amunduzbaev	Amusement Park (CEOI19_amusementpark)	C++17	63 / 100	3031 ms	29700 KiB

amusementpark

#include "bits/stdc++.h"
using namespace std;
 
#define ar array
typedef int64_t ll;
//~ #define int ll
 
const int mod = 119 << 23 | 1;
const int N = 18;
unordered_map<int, int> dp[1 << N];
int is[N];
 
int bp(int a, int b){
	int c = 1;
	while(b){
		if(b & 1) c = c * 1ll * a % mod;
		a = a * 1ll * a % mod, b >>= 1;
	} return c;
}
 
signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n, m; cin>>n>>m;
	for(int i=0;i<m;i++){
		int a, b; cin>>a>>b;
		--a, --b;
		is[a] |= (1 << b);
		is[b] |= (1 << a);
	}
	
	dp[0][0] = 1;
	for(int mask=0;mask < (1 << n);mask++){
		for(int j=0;j<n;j++){
			if(mask >> j & 1) continue;
			
			int on_j = mask | (1 << j);
			for(int m2=on_j;m2 < (1 << n); m2++, m2 |= on_j){
				int bad = m2 ^ on_j;
				if(!dp[mask].count(bad)) continue;
				int edge_out = ((1 << n) - 1) ^ (is[j] ^ (is[j] & mask));
				int bad2 = ((bad | ((1 << j) - 1)) ^ (mask & ((1 << j) - 1))) & edge_out;
				int& res = dp[on_j][bad2];
				res = (res + dp[mask][bad]);
				if(res >= mod) res -= mod;
			}
		}
	}
	
	int res = dp[(1 << n) - 1][0];
	//~ cout<<res<<"\n";
	cout<<res * 1ll * bp(2, mod - 2) % mod * m % mod<<"\n";
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 21 / 21
• Subtask 5: 0 / 37