Submission #47472

#	Time	Username	Problem	Language	Result	Execution time	Memory
47472		Just_Solve_The_Problem	Asceticism (JOI18_asceticism)	C++11	0 / 100	5 ms	1132 KiB

asceticism

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define eb emplace_back
#define ll long long
#define pii pair < int, int >
#define fr first
#define sc second
#define mk make_pair
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define ok puts("ok");
#define whatis(x) cerr << #x << " = " << x << endl;
#define pause system("pause");
#define random rand() ^ (rand() << 5)

const int N = (int)1e5 + 7;
const int inf = (int)1e9 + 7;
int mod = (int)1e9 + 7;

ll fact[N];

ll mult(ll a, ll b) {
  return a * b % mod;
}

void precalc() {
  fact[0] = 1;
  for (ll i = 1; i < N; i++) {
    fact[i] = mult(fact[i - 1], i);
  }
}

ll binpow(ll a, int n) {
  ll res = 1;
  while (n > 0) {
    if (n & 1) {
      res = mult(res, a);
    }
    a = mult(a, a);
    n >>= 1;
  }
  return res;
}

ll cnk(ll n, ll k) {
  if (k > n) return 0;
  return mult(mult(fact[n], binpow(fact[k], mod - 2)), binpow(fact[n - k], mod - 2));
}

int n, m;

main() {
  precalc();
  scanf("%d %d", &n, &m);
  m--;
  ll ans = 0;
  for (int k = 0; k <= m + 1; k++) {
    if (k & 1) {
      ans -= mult(cnk(n + 1, k), binpow(m + 1 - k, n));
    } else {
      ans += mult(cnk(n + 1, k), binpow(m + 1 - k, n));
    }
  }
  cout << ans;
}

Compilation message (stderr)

asceticism.cpp:55:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
asceticism.cpp: In function 'int main()':
asceticism.cpp:57:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &n, &m);
   ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 20
• Subtask 3: 0 / 25
• Subtask 4: 0 / 51