Submission #201071

#	Time	Username	Problem	Language	Result	Execution time	Memory
201071		mraron	Zapina (COCI20_zapina)	C++14	110 / 110	170 ms	1400 KiB

zapina

#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<cassert>
#include<cassert>
#include<unordered_map>
#include<unordered_set>
#include<functional>
#include<queue>
#include<stack>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<sstream>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<numeric>
#include<random>
#include<chrono>
#include<bitset>
using namespace std;

#define all(x) (x).begin(), (x).end()
#define pb push_back
#define xx first
#define yy second
#define sz(x) (int)(x).size()
#define gc getchar
#define IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define mp make_pair

#ifndef ONLINE_JUDGE
#  define LOG(x) (cerr << #x << " = " << (x) << endl)
#else
#  define LOG(x) ((void)0)
#endif

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const double PI=3.1415926535897932384626433832795;
const ll INF = 1LL<<62;
const ll MINF = -1LL<<62;

template<typename T> T getint() {
	T val=0;
	char c;
	
	bool neg=false;
	while((c=gc()) && !(c>='0' && c<='9')) {
		neg|=c=='-';
	}

	do {
		val=(val*10)+c-'0';
	} while((c=gc()) && (c>='0' && c<='9'));

	return val*(neg?-1:1);
}

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); uniform_int_distribution<int>(0, n-1)(rng)


const ll mod=1e9+7;
ll dp[351][351];
ll f[351];
ll inv[351];

ll fp(ll a, ll b) {
	if(b==0) return 1;
	ll fel=fp(a,b/2);
	ll ans=fel*fel%mod;
	if(b&1) ans=(ans*a)%mod;
	return ans;
}

ll nc(ll a, ll b) {
	return f[a]*inv[b]%mod*inv[a-b]%mod;
}


int main() {
	IO;
	f[0]=1;
	for(int i=1;i<351;++i) f[i]=f[i-1]*i%mod;
	for(int i=0;i<351;++i) inv[i]=fp(f[i],mod-2);
	
	ll n;
	cin>>n;
	dp[0][n]=1;
	for(int i=1;i<=n;++i) {
		for(int j=0;j<=n;++j) {
			for(int k=0;k<=j;++k) {
				if(k==i) continue ;
				dp[i][j-k]+=dp[i-1][j]*nc(j,k);
				dp[i][j-k]%=mod;
			}
		}
	}
	ll res=(fp(n,n)-dp[n][0])%mod;
	if(res<0) res+=mod;
	cout<<res<<"\n";
	return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 33 / 33
• Subtask 3: 55 / 55