Submission #852857

#	Time	Username	Problem	Language	Result	Execution time	Memory
852857		hngwlog	Binaria (CCO23_day1problem1)	C++14	25 / 25	183 ms	74776 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define _size(x) (int)x.size()
#define BIT(i, x) ((x >> i) & 1)
#define MASK(n) ((1 << n) - 1)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; i++)
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; i++)
#define FORD(i, a, b) for (int i = a, _b = (b); i >= _b; i--)
#define FORB1(i, mask) for (int i = mask; i > 0; i ^= i & - i)
#define FORB0(i, n, mask) for (int i = ((1 << n) - 1) ^ mask; i > 0; i ^= i & - i)
#define FORALL(i, a) for (auto i: a)
#define fastio ios_base::sync_with_stdio(0); cin.tie(0);

const int mod = 1e6 + 3;

vector<int> root, p, ivp;

int getroot(int u) {

    return root[u] == u ? u : (root[u] = getroot(root[u]));
}

bool unite(int u, int v) {

    u = getroot(u), v = getroot(v);
    if (u == v) return false;
    root[v] = u;
    return true;
}

int _pow(int a, int x) {

    if (!x) return 1;
    int t = _pow(a, x / 2);
    t = (1LL * t * t) % mod;
    if (x % 2) t = (1LL * t * a) % mod;
    return t;
}

int C(int k, int n) {

    return (1LL * p[n] * ivp[k] * ivp[n - k]) % mod;
}

int main() {
    fastio;

    int n, k;
    cin >> n >> k;
    vector<int> a(n - k + 2);
    FOR(i, 1, n - k + 1) cin >> a[i];
    vector<int> b(n + 1, - 1);
    root.resize(n + 1);
    FOR(i, 1, n) root[i] = i;
//    vector<int> deg(n + 1);
    FOR(i, 2, n - k + 1) {
        if (a[i] == a[i - 1]) {
            unite(i - 1, i + k - 1);
            continue;
        }
        if (a[i] < a[i - 1]) b[i + k - 1] = 0, b[i - 1] = 1;
        else b[i + k - 1] = 1, b[i - 1] = 0;
//        deg[i - 1]++;
//        deg[i + k - 1]++;
    }
    vector<vector<int>> adj(n + 1);
    vector<int> ids;
    FOR(i, 1, n) {
        adj[getroot(i)].push_back(i);
        ids.push_back(getroot(i));
    }
    sort(ids.begin(), ids.end());
    ids.resize(unique(ids.begin(), ids.end()) - ids.begin());
    FORALL(id, ids) {
        int value = - 1;
        FORALL(u, adj[id]) {
            if (b[u] == - 1) continue;
            if (value == - 1) value = b[u];
            else if (value != b[u]) {
                cout << 0 << '\n';
                return 0;
            }
        }
        if (value == - 1) continue;
        FORALL(u, adj[id]) b[u] = value;
    }
//    int cnt = 0;
//    FOR(i, 1, n) if (!deg[i]) cnt++;
    p.resize(n + 1);
    p[0] = 1;
    FOR(i, 1, n) p[i] = (1LL * p[i - 1] * i) % mod;
    ivp.resize(n + 1);
    ivp[n] = _pow(p[n], mod - 2);
    FORD(i, n - 1, 0) ivp[i] = (1LL * ivp[i + 1] * (i + 1)) % mod;
    int cnt = 0, sum = 0;
    FOR(i, 1, k) if (b[i] == - 1) cnt++; else sum += b[i];
    cout << C(a[1] - sum, cnt) << '\n';
    return 0;
}

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