Submission #129812

#	Time	Username	Problem	Language	Result	Execution time	Memory
129812		nandonathaniel	Kangaroo (CEOI16_kangaroo)	C++14	6 / 100	19 ms	736 KiB

kangaroo

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const LL MOD=1000000007;

LL dp[(1<<20)][20][2];

int main(){
	ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	LL n,s,t;
	cin >> n >> s >> t;
	s--;t--;
	dp[(1<<s)][s][0]=1;
	dp[(1<<s)][s][1]=1;
	for(LL i=0;i<(1<<n);i++){
		for(LL j=0;j<n;j++){
			if(i & (1<<j)){
				for(LL k=0;k<n;k++){
					if(!(i & (1<<k))){
						if(j>k)dp[i+(1<<k)][k][0]=(dp[i+(1<<k)][k][0]+dp[i][j][1])%MOD;
						else dp[i+(1<<k)][k][1]=(dp[i+(1<<k)][k][1]+dp[i][j][0])%MOD;
					}
				}
			}
		}
	}
	cout << (dp[(1<<n)-1][t][0]+dp[(1<<n)-1][t][1])%MOD << endl;
	return 0;
}

• Subtask 1: 6 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49