Submission #967997

#	Time	Username	Problem	Language	Result	Execution time	Memory
967997		Gromp15	Binaria (CCO23_day1problem1)	C++17	25 / 25	230 ms	106144 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define ar array
#define db double
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define rint(l, r) uniform_int_distribution<int>(l, r)(rng)
template<typename T> bool ckmin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template<typename T> bool ckmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }
const int mod = 1e6 + 3;
void fadd(int &a, int b) {
	a += b;
	if (a >= mod) a -= mod;
}
int binpow(int a, int b) {
	int r = 1;
	for (; b; a = (ll)a*a%mod, b >>= 1) if (b & 1) r = (ll)r*a%mod;
	return r;
}
vector<int> facs, invfacs;
void init(int n) {
	facs.resize(n+1), invfacs.resize(n+1);
	facs[0] = 1;
	for (int i = 1; i <= n; i++) facs[i] = (ll)facs[i-1] * i % mod;
	invfacs[n] = binpow(facs[n], mod - 2);
	for (int i = n - 1; i >= 0; i--) invfacs[i] = (ll)invfacs[i+1] * (i+1) % mod;
}
int choose(int a, int b) {
	return ((ll)facs[a] * invfacs[b] % mod) * invfacs[a-b] % mod;
}
void test_case() {
	int n, k;
	cin >> n >> k;
	vector<int> a(n - k + 1);
	for (int &x : a) cin >> x;
	vector<vector<ar<int, 2>>> adj(n);
	for (int i = 0; i < n-k; i++) {
		int w = a[i+1] - a[i];
		adj[i].push_back({i + k, w});
		adj[i + k].push_back({i, -w});
	}
	vector<int> col(n);
	vector<bool> vis(n);
	auto dfs = [&](auto&& s, int v) -> void {
		vis[v] = 1;
		for (auto [u, w] : adj[v]) {
			if (!vis[u]) {
				col[u] = col[v] + w;
				s(s, u);
			}
			assert(col[u] == (col[v] + w));
		}
	};
	for (int i = 0; i < n; i++) if (!vis[i]) dfs(dfs, i);
	vector<int> state(k, -1);
	for (int i = 0; i < k; i++) {
		int b = 0;
		for (int j = i + k; j < n; j += k) {
			if (abs(col[j]) > 1) {
				cout << 0 << '\n'; return;
			}
			if (col[j] < 0) b |= 1;
			if (col[j] > 0) b |= 2;
		}
		if (b == 3) {
			cout << 0 << '\n'; return;
		}
		if (b == 1) state[i] = 1;
		if (b == 2) state[i] = 0;
	}
	ar<int, 3> who{};
	for (int i = 0; i < k; i++) {
		if (state[i] == -1) who[2]++;
		else if (state[i] == 0) who[0]++;
		else who[1]++;
	}
	if (who[1] > a[0] || who[2] + who[1] < a[0]) {
		cout << 0 << '\n'; return;
	}
	cout << choose(who[2], a[0] - who[1]) << '\n';


}
int main() {
    cin.tie(0)->sync_with_stdio(0);
	init(1e6);
    int t = 1;
//    cin >> t;
    while (t--) test_case();
}

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 7 / 7