Submission #633966

#	Time	Username	Problem	Language	Result	Execution time	Memory
633966		vovamr	Anagramistica (COCI21_anagramistica)	C++17	110 / 110	7 ms	476 KiB

anagramistica

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define ll long long
#define ld long double
#define sz(x) ((int)(x).size())
#define all(x) 	(x).begin(), (x).end()
#define pb push_back
#define mpp make_pair
#define ve vector
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const ll inf = 1e18; const int iinf = 1e9;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline bool chmin(T& a, T b) { return (a > b ? a = b, 1 : 0); }
template <typename T> inline bool chmax(T& a, T b) { return (a < b ? a = b, 1 : 0); }

constexpr int md = 1e9 + 7; constexpr int iv2 = (md + 1) / 2;
inline int add(int a, int b) { a += b; if(a>=md){a-=md;} return a; }
inline int sub(int a, int b) { a -= b; if(a<0){a+=md;} return a; }
inline int mul(int a, int b) { return (ll)a * b % md; }
inline int bp(int a, int n) { int res = 1;
	for (; n; n >>= 1, a = mul(a, a)) {
		if (n & 1) res = mul(res, a);
	} return res;
}
inline int inv(int a) { return bp(a, md - 2); }

const int N = 2e3 + 10;
int f[N], iff[N];
inline void calc() {
	f[0] = 1;
	for (int i = 1; i < N; ++i) f[i] = mul(f[i - 1], i);
	iff[N - 1] = inv(f[N - 1]);
	for (int i = N - 2; ~i; --i) iff[i] = mul(iff[i + 1], i + 1);
}
inline int C(int n, int k) {
	return mul(f[n], mul(iff[k], iff[n - k]));
}

inline void solve() { calc();

	int n, k;
	cin >> n >> k;
	unordered_map<string,int> mp;
	mp.reserve(1024); mp.max_load_factor(0.25);

	for (int i = 0; i < n; ++i) {
		string s; cin >> s;
		sort(all(s));

		++mp[s];
	}

	ve<int> dp(k + 1); dp[0] = 1;
	for (auto &[str, cnt] : mp) {
		ve<int> f(k + 1);
		for (int i = 0; i <= cnt; ++i) {
			int c = i * (i - 1) / 2;
			for (int s = 0; s + c <= k; ++s) {
				f[s + c] = add(f[s + c], mul(dp[s], C(cnt, i)));
			}
		} dp.swap(f);
	}

	cout << dp[k];
}

signed main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int q = 1; // cin >> q;
	while (q--) solve();
	cerr << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
}

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 70 / 70