Submission #1038817

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038817		vjudge1	Binaria (CCO23_day1problem1)	C++17	25 / 25	106 ms	20948 KiB

Main

// Dit me fryingduc

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

#define int long long
#define fore(i, a, b) for (int i = (a); i <= (b); i++)
#define pb emplace_back
const int mod = 1e6 + 3;

int binpow(int a, int b)
{
  if (b == 0) return 1ll;
  int ans = binpow(a, b / 2ll);
  return ans * ans % mod * (b & 1ll ? a : 1ll) % mod;
}

int nCk(int n, int k)
{
  int ans = 1;
  if (k > n || n < 0 || k < 0) return 0;
  fore(i, k + 1, n) ans = ans * i % mod;
  fore(i, 1, n - k) ans = ans * binpow(i, mod - 2) % mod;
  return ans;
}

signed main()
{
  cin.tie(0)->sync_with_stdio(0);
  int n, k;
  cin >> n >> k;
  vector<int> a(n - k + 2), x(n + 1, -1);
  fore(i, 1, n - k + 1) cin >> a[i];
  fore(i, 2, n - k + 1) if (abs(a[i] - a[i - 1]) > 1) return cout << 0, 0;
  fore(i, 2, n - k + 1)
  {
    if (a[i] - a[i - 1] == 1) 
      x[i + k - 1] = 1,
      x[i - 1] = 0;
    else if (a[i] - a[i - 1] == -1)
      x[i + k - 1] = 0,
      x[i - 1] = 1;
    else
      x[i + k - 1] = x[i - 1];
  }
  for (int i = n - k; i >= 1; i--)
    if (a[i] == a[i + 1])
      x[i] = x[i + k];
  int use = 0;
  fore(i, 1, k)
    use += (x[i] == -1),
    a[1] -= (x[i] == 1);
  cout << nCk(use, a[1]);
  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