Submission #614047

#	Time	Username	Problem	Language	Result	Execution time	Memory
614047		IWTIM	Magneti (COCI21_magneti)	C++14	110 / 110	236 ms	105672 KiB

Main

# include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = long double; // or double, if TL is tight
using str = string; // yay python! 
 
// pairs
using pii = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
#define mp make_pair
#define f first
#define s second
 
#define tcT template<class T
#define tcTU tcT, class U
// ^ lol this makes everything look weird but I'll try it
tcT> using V = vector<T>; 
tcT, size_t SZ> using AR = array<T,SZ>; 
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pii>;
using vpl = V<pl>;
using vpd = V<pd>;
 
// vectors
// oops size(x), rbegin(x), rend(x) need C++17
#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()
 
#define lb lower_bound
#define ub upper_bound
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_,a)
#define each(a,x) for (auto& a: x)
const int MOD = 998244353;
const int MX = 2e5+5;
const ll BIG = 1e18; // not too close to LLONG_MAX
const db PI = acos((db)-1);
const int dx[4]{1,0,-1,0}, dy[4]{0,1,0,-1}; // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 
template<class T> using pqg = priority_queue<T,vector<T>,greater<T>>;
struct DSU {
	vi e; void init(int N) { e = vi(N,-1); }
	int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); } 
	bool sameSet(int a, int b) { return get(a) == get(b); }
	int size(int x) { return -e[get(x)]; }
	bool unite(int x, int y) { // union by size
		x = get(x), y = get(y); if (x == y) return 0;
		if (e[x] > e[y]) swap(x,y);
		e[x] += e[y]; e[y] = x; return 1;
	}
};
/*
inline namespace Helpers {
	//////////// is_iterable
	// https://stackoverflow.com/questions/13830158/check-if-a-variable-type-is-iterable
	// this gets used only when we can call begin() and end() on that type
	tcT, class = void> struct is_iterable : false_type {};
	tcT> struct is_iterable<T, void_t<decltype(begin(declval<T>())),
	                                  decltype(end(declval<T>()))
	                                 >
	                       > : true_type {};
	tcT> constexpr bool is_iterable_v = is_iterable<T>::value;
 
	//////////// is_readable
	tcT, class = void> struct is_readable : false_type {};
	tcT> struct is_readable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cin >> declval<T&>()), istream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_readable_v = is_readable<T>::value;
 
	//////////// is_printable
	// // https://nafe.es/posts/2020-02-29-is-printable/
	tcT, class = void> struct is_printable : false_type {};
	tcT> struct is_printable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cout << declval<T>()), ostream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_printable_v = is_printable<T>::value;
}*/
#define f first
#define s second
#define int long long
#define pb push_back
const int N = 1e4 + 1000,mod = 1e9 + 7;
int n,l,a[N],per[N],a1[N],fq[N],inv[N],idx[N],k,ans;
int dp[58][58][N];
int f_p(int base, int power) {
	int result = 1;	
	while (power > 0) {
		if (power % 2 == 1) {
			result = (result * base) % mod; 
		}
		power /= 2;
		base = (base*base) % mod;
	}
	return result;
}
int C(int n, int k) {
	int xx = (inv[k] * inv[n - k]) % mod;
	return (fq[n] * xx)%mod;
}
main() {
	cin>>n>>l;
	inv[0] = fq[0] = 1;
	for (int i = 1; i <= n + l; i++) {
		fq[i] = fq[i - 1] * i; fq[i] %= mod;
		inv[i] = f_p(fq[i], mod - 2);
	}
	for (int i = 1; i <= n; i++) {
		cin>>a[i];
		per[i] = i;
	}
	sort(a + 1, a + n + 1);
	dp[0][0][0] = 1;
	for (int i = 1; i <= n; i++) {
	     //cout<<i<<endl;
	     for(int j = 1; j <= i; j++) {
	          for (int d = 1; d <= l; d++) {
	               if (d - a[i] >= 0)
	               dp[i][j][d] += 2 * j * dp[i - 1][j][d - a[i]], dp[i][j][d] %= mod;
	               if (d) dp[i][j][d] += dp[i - 1][j - 1][d - 1], dp[i][j][d] %= mod;
	               if (d - 2*a[i] + 1>= 0)
	               dp[i][j][d] += (2*C(j + 1,2)*dp[i - 1][j + 1][d - 2*a[i] + 1]) % mod,  dp[i][j][d] %= mod;
	               //cout<<j<<" "<<d<<" "<<dp[i][j][d]<<endl;
	          }
	     }
	}
	for (int i = 0; i <= l; i++) {
	      k = l - i;
	     ans += (dp[n][1][i] * C(n + k, k))%mod; ans %= mod;
	}
	cout<<ans<<endl;
	/*
	do {
		for (int i = 1; i <= n; i++) {
			a1[per[i]] = a[i];
			//cout<<a1[i]<<" ";
		}
		idx[1] = 1;
		for (int i = 2; i <= n; i++) {
			idx[i] = idx[i - 1] + max(a1[i], a1[i - 1]);	
		}
		if (idx[n] <= l) {
			k = l - idx[n];
			ans += C(n + k, k); ans %= mod;
		}
		//cout<<"\n";
	}while(next_permutation(per + 1, per + n + 1));*/
}

Compilation message (stderr)

Main.cpp:122:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  122 | main() {
      | ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 50 / 50