Submission #972446

#	Time	Username	Problem	Language	Result	Execution time	Memory
972446		LCJLY	Asceticism (JOI18_asceticism)	C++14	49 / 100	94 ms	144212 KiB

asceticism

#include <bits/stdc++.h>
using namespace std;
	
#define int long long 
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << "  " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << "  " << j << " " << #i << "  " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<long long,long long>pii;
typedef pair<int,pii>pi2;
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

int n,k;
int memo[3005][3005];
const int mod=1e9+7;

int dp(int index, int day){
	if(index==n+1){
		if(day==k) return 1;
		else return 0;
	}
	if(memo[index][day]!=-1) return memo[index][day];
	int ans=0;
	ans=(ans+dp(index+1,day)*(day))%mod;
	ans=(ans+dp(index+1,day+1)*(index-day))%mod;
	//show3(index,index,day,day,ans,ans);
	return memo[index][day]=ans;
}

void solve(){
	cin >> n >> k;
	memset(memo,-1,sizeof(memo));
	cout << dp(1,0);
}
 
int32_t main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int t=1;
	//freopen("in.txt","r",stdin);
	//cin >> t;
	while(t--){
		solve();
	}
}

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 51