Submission #366711

# Submission time Handle Problem Language Result Execution time Memory
366711 2021-02-15T07:03:55 Z Kevin_Zhang_TW Asceticism (JOI18_asceticism) C++17
100 / 100
30 ms 2796 KB
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T L, T R) { while (L != R) cerr << *L << " \n"[next(L) == R], ++L; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

const int MAX_N = 300010, p = 1e9 + 7;

int n, k;
ll fa[MAX_N], fai[MAX_N], inv[MAX_N];

void init() {
	for (int i : {0, 1})
		fa[i] = fai[i] = inv[i] = 1;
	for (int i = 2;i <= n;++i) {
		fa[i] = fa[i-1] * i % p;
		inv[i] = (p - p / i) * inv[p % i] % p;
		fai[i] = inv[i] * fai[i-1] % p;
	}
}

ll C(int N, int M) { return N < M ? 0 : fa[N] * fai[M] % p * fai[N - M] % p; }

ll bin_pow(ll v, ll t) {
	ll res = 1;
	for (;t;t>>=1, v = v * v % p)
		if (t&1) res = res * v % p;
	return res;
}

// The problem is calculate # permutation P that
// # P_i < P_{i-1} = K
//

ll ginv(ll v) { return bin_pow(v, p - 2); }

// area of N dimension sum(X_i) <= K equals to K^N / N!
// if K <= sum(Y) < K+1
// it means that the number of X_i < X_{i-1} = K

// the area of sum(Y) < a
ll area(ll sum) {
	return bin_pow(sum, n) * fai[n] % p ;
}

ll calsum(int a) {
	ll res = 0;
	for (int i = 0;i <= n;++i) {
		if (i > a) break;
		ll si = i & 1 ? -1 : 1;
		res += si * area(a - i) * C(n, i) % p;
	}
	res %= p;
	if (res < 0) res += p;
	return res;
}

int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);

	cin >> n >> k; 
	
	--k;

	init();

	ll all = calsum(n), ok = calsum(k + 1) - calsum(k) ;

	ll res = ok * ginv(all) % p;

	if (res < 0) res += p;

	res = res * fa[n] % p;

	// res is the posibility

	DE(all, ok, fa[n]);

	cout << res << '\n';

}

Compilation message

asceticism.cpp: In function 'int32_t main()':
asceticism.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
asceticism.cpp:88:2: note: in expansion of macro 'DE'
   88 |  DE(all, ok, fa[n]);
      |  ^~
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 364 KB Output is correct
29 Correct 1 ms 364 KB Output is correct
30 Correct 1 ms 384 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 364 KB Output is correct
29 Correct 1 ms 364 KB Output is correct
30 Correct 1 ms 384 KB Output is correct
31 Correct 12 ms 2668 KB Output is correct
32 Correct 12 ms 2688 KB Output is correct
33 Correct 13 ms 2668 KB Output is correct
34 Correct 16 ms 2760 KB Output is correct
35 Correct 26 ms 2668 KB Output is correct
36 Correct 28 ms 2668 KB Output is correct
37 Correct 30 ms 2668 KB Output is correct
38 Correct 4 ms 748 KB Output is correct
39 Correct 14 ms 2028 KB Output is correct
40 Correct 19 ms 2796 KB Output is correct