#include <bits/stdc++.h>
using namespace std;
const int N = 110;
const int md = 1e9 + 7;
int n, L;
int a[N];
int f[N][N][1010][2][2];
void add(int &x, int y) { x += y; while(x >= md) x -= md; if (x < 0) x += md; }
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> n >> L;
if (n == 1) {
printf("1\n"); return 0;
}
for (int i = 1; i <= n; ++i) cin >> a[i];
sort(a + 1, a + n + 1);
for (int i = n; i >= 2; --i) a[i] = a[i] - a[i-1]; a[1] = 0;
f[0][0][0][0][0] = 1;
for (int i = 0; i < n; ++i) for (int j = 0; j <= i; ++j) for (int s = 0; s <= L; ++s) {
for (int l = 0; l < 2; ++l) for (int r = 0; r < 2; ++r) {
int cur = f[i][j][s][l][r]; if (cur == 0) continue;
int ns = s + (2 * j - l - r) * a[i + 1]; if (ns > L) continue;
// push a[i] to the front or the back of a component
if (!l) add(f[i + 1][j][ns][1][r], 1LL * cur * (j - (i != n - 1 ? r : 0)) % md);
if (!r) add(f[i + 1][j][ns][l][1], 1LL * cur * (j - (i != n - 1 ? l : 0)) % md);
add(f[i + 1][j][ns][l][r], 1LL * cur * (2 * j - l - r) % md);
// use a[i] to connect two distinct components
if (j >= 1) add(f[i + 1][j - 1][ns][l][r], 1LL * cur * ((j - l - r) * (j - 1) + (i == n - 1 ? l * r : 0)) % md);
// create a new component
if (!l) add(f[i + 1][j + 1][ns][1][r], cur);
if (!r) add(f[i + 1][j + 1][ns][l][1], cur);
add(f[i + 1][j + 1][ns][l][r], cur);
}
}
int ans = 0;
for (int s = 0; s <= L; ++s) {
add(ans, f[n][1][s][1][1]);
}
cout << ans << '\n';
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 2 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 3 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 4 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 5 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 6 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 7 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 8 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 9 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 10 |
Correct |
0 ms |
193132 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 2 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 3 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 4 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 5 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 6 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 7 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 8 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 9 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 10 |
Correct |
0 ms |
193132 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 2 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 3 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 4 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 5 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 6 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 7 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 8 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 9 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 10 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 11 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 12 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 13 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 14 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 15 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 16 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 17 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 18 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 19 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 20 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 21 |
Correct |
0 ms |
193132 KB |
Output is correct |
| 22 |
Correct |
139 ms |
193132 KB |
Output is correct |
| 23 |
Correct |
79 ms |
193132 KB |
Output is correct |
| 24 |
Correct |
83 ms |
193132 KB |
Output is correct |
| 25 |
Correct |
79 ms |
193132 KB |
Output is correct |
| 26 |
Correct |
79 ms |
193132 KB |
Output is correct |
| 27 |
Correct |
36 ms |
193132 KB |
Output is correct |
| 28 |
Correct |
49 ms |
193132 KB |
Output is correct |
| 29 |
Correct |
99 ms |
193132 KB |
Output is correct |
| 30 |
Correct |
96 ms |
193132 KB |
Output is correct |
