Submission #165207

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
165207	2019-11-26 03:05:08	coloredrabbit	Ω (kriii4_P3)	C++17	0 / 100	2 ms	376 KiB

P3

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#include <cstdio>
using ll = long long;
const ll MOD = 1e9 + 7;
ll _pow(ll a, int n) {
  if (n == 0) return 1;
  ll ret = _pow(a, n / 2);
  ret = (ret * ret) % MOD;
  if (n & 1) ret = (ret * a) % MOD;
  return ret;
}
ll gcd(ll p, ll q) { return !q ? p : gcd(q, p % q); }
ll rev(ll x) { return _pow(x, MOD - 2); }
int main() {
  int P, Q, N, K;
  ll v, ans = 0, A, B, g, X;
  scanf("%d%d%d%d", &P, &Q, &N, &K);
  if (K == 0 || Q == P) puts("0");
  else if (K == N || Q == 0) puts("1");
  else {
    if (2 * Q == P)
      ans = K * rev(N) % MOD;
    else {
      v = Q * rev(P - Q);
      ans = ((1 - _pow(v, K) + MOD) % MOD) * (rev(1 - _pow(v, N) + MOD) % MOD) % MOD;
    }
    printf("%lld", ans);
  }
  return 0;
}
 
 
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Compilation message (stderr)

P3.cpp: In function 'int main()':
P3.cpp:15:17: warning: unused variable 'A' [-Wunused-variable]
  ll v, ans = 0, A, B, g, X;
                 ^
P3.cpp:15:20: warning: unused variable 'B' [-Wunused-variable]
  ll v, ans = 0, A, B, g, X;
                    ^
P3.cpp:15:23: warning: unused variable 'g' [-Wunused-variable]
  ll v, ans = 0, A, B, g, X;
                       ^
P3.cpp:15:26: warning: unused variable 'X' [-Wunused-variable]
  ll v, ans = 0, A, B, g, X;
                          ^
P3.cpp:16:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d", &P, &Q, &N, &K);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100