#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
typedef long long ll;
const int MOD = 1e9 + 7;
ll add(ll x, ll y) {return ((x % MOD) + (y % MOD)) % MOD;}
ll prod(ll x, ll y) {return ((x % MOD) * (y % MOD)) % MOD;}
ll sub(ll x, ll y) {return ((x - y) % MOD + MOD) % MOD;}
ll pwer(ll x, ll y) {
if(y == 0) return 1;
ll half = pwer(x, y / 2);
half = prod(half, half);
if(y & 1) return prod(half, x);
else return half;
}
const int N = 1e3 + 3;
int n;
ll fact[N + 1], inv[N + 1];
void preprocess() {
fact[0] = 1;
for(int i = 1; i <= N; i++) fact[i] = prod(fact[i - 1], i);
inv[N] = pwer(fact[N], MOD - 2);
for(int i = N - 1; i >= 0; i--) inv[i] = prod(inv[i + 1], i + 1);
}
ll C(ll k, ll n) {
if(k > n) return 0;
return prod(fact[n], prod(inv[k], inv[n - k]));
}
void input() {
cin >> n;
}
namespace subtask_two {
ll compute(int mask) {
ll candies = n, remains = 0, ways = 1;
for(int i = 0; i < n; i++) {
if(mask & (1 << i)) {
ways = prod(ways, C(i + 1, candies));
candies -= i + 1;
}else remains++;
}
ways = prod(ways, pwer(remains, candies));
if(candies < 0) return 0;
else return ways;
}
void solve() {
ll total = pwer(n, n), answer = 0;
for(int mask = 0; mask < (1 << n); mask++) {
if(__builtin_popcount(mask) % 2 == 0) answer = add(answer, compute(mask));
else answer = sub(answer, compute(mask));
}
cout << sub(total, answer) << endl;
}
bool check() {
return n <= 20;
}
}
namespace subtask_three {
ll dp[N][N][2];
void solve() {
dp[0][0][0] = 1;
for(int i = 1; i <= n; i++) {
for(int j = 0; j <= n; j++) {
for(int c = 0; c <= j; c++) {
if(c == i)
dp[i][j][1] = add(dp[i][j][1], add(prod(dp[i - 1][j - c][0], C(c, j)), prod(dp[i - 1][j - c][1], C(c, j))));
else {
dp[i][j][0] = add(dp[i][j][0], prod(dp[i - 1][j - c][0], C(c, j)));
dp[i][j][1] = add(dp[i][j][1], prod(dp[i - 1][j - c][1], C(c, j)));
}
}
}
}
cout << dp[n][n][1] << endl;
}
bool check() {
return n <= 350;
}
}
void process() {
if(subtask_two::check()) return subtask_two::solve(), void();
if(subtask_three::check()) return subtask_three::solve(), void();
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
preprocess();
input();
process();
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Correct |
1 ms |
592 KB |
Output is correct |
4 |
Correct |
1 ms |
336 KB |
Output is correct |
5 |
Correct |
1 ms |
336 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Correct |
1 ms |
592 KB |
Output is correct |
4 |
Correct |
1 ms |
336 KB |
Output is correct |
5 |
Correct |
1 ms |
336 KB |
Output is correct |
6 |
Correct |
1 ms |
336 KB |
Output is correct |
7 |
Correct |
1 ms |
336 KB |
Output is correct |
8 |
Correct |
1 ms |
336 KB |
Output is correct |
9 |
Correct |
2 ms |
336 KB |
Output is correct |
10 |
Correct |
3 ms |
336 KB |
Output is correct |
11 |
Correct |
4 ms |
336 KB |
Output is correct |
12 |
Correct |
7 ms |
480 KB |
Output is correct |
13 |
Correct |
14 ms |
476 KB |
Output is correct |
14 |
Correct |
29 ms |
476 KB |
Output is correct |
15 |
Correct |
57 ms |
336 KB |
Output is correct |
16 |
Correct |
125 ms |
336 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Correct |
1 ms |
592 KB |
Output is correct |
4 |
Correct |
1 ms |
336 KB |
Output is correct |
5 |
Correct |
1 ms |
336 KB |
Output is correct |
6 |
Correct |
1 ms |
336 KB |
Output is correct |
7 |
Correct |
1 ms |
336 KB |
Output is correct |
8 |
Correct |
1 ms |
336 KB |
Output is correct |
9 |
Correct |
2 ms |
336 KB |
Output is correct |
10 |
Correct |
3 ms |
336 KB |
Output is correct |
11 |
Correct |
4 ms |
336 KB |
Output is correct |
12 |
Correct |
7 ms |
480 KB |
Output is correct |
13 |
Correct |
14 ms |
476 KB |
Output is correct |
14 |
Correct |
29 ms |
476 KB |
Output is correct |
15 |
Correct |
57 ms |
336 KB |
Output is correct |
16 |
Correct |
125 ms |
336 KB |
Output is correct |
17 |
Correct |
184 ms |
2748 KB |
Output is correct |
18 |
Correct |
2 ms |
760 KB |
Output is correct |
19 |
Correct |
42 ms |
1408 KB |
Output is correct |
20 |
Correct |
1 ms |
760 KB |
Output is correct |
21 |
Correct |
257 ms |
2944 KB |
Output is correct |
22 |
Correct |
29 ms |
1364 KB |
Output is correct |
23 |
Correct |
3 ms |
592 KB |
Output is correct |
24 |
Correct |
53 ms |
1612 KB |
Output is correct |
25 |
Correct |
37 ms |
1352 KB |
Output is correct |
26 |
Correct |
71 ms |
1864 KB |
Output is correct |
27 |
Correct |
352 ms |
3400 KB |
Output is correct |
28 |
Correct |
352 ms |
3544 KB |
Output is correct |
29 |
Correct |
368 ms |
3656 KB |
Output is correct |
30 |
Correct |
358 ms |
3656 KB |
Output is correct |
31 |
Correct |
373 ms |
3656 KB |
Output is correct |
32 |
Correct |
368 ms |
3536 KB |
Output is correct |
33 |
Correct |
385 ms |
3636 KB |
Output is correct |
34 |
Correct |
367 ms |
3664 KB |
Output is correct |
35 |
Correct |
383 ms |
3596 KB |
Output is correct |
36 |
Correct |
381 ms |
3656 KB |
Output is correct |
37 |
Correct |
386 ms |
3708 KB |
Output is correct |