#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const ll MOD = 1e9 + 7;
int a[102];
ll dp[101][101][1001][3];
// dp[i][j][k][m] = No. of ways to insert first i buildings into permutation with
// j connected components, total cost k, and m ends of permutation inserted
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, l;
cin >> n >> l;
for (int i = 1; i <= n; i++) cin >> a[i];
sort(a + 1, a + n + 1);
a[n + 1] = 10000;
dp[0][0][0][0] = 1;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= i; j++) {
for (int k = 0; k <= l; k++) {
for (int m = 0; m <= 2; m++) {
int cost_diff = (2 * j - m) * (a[i + 1] - a[i]);
if (cost_diff > k) continue;
// Case 1: we form a new connected component in the middle
dp[i][j][k][m] += dp[i - 1][j - 1][k - cost_diff][m];
// Case 2: we form a new connected component at the end
if (m) dp[i][j][k][m] += (3 - m) * dp[i - 1][j - 1][k - cost_diff][m - 1];
// Case 3: we append a[i] to the end of a component so that it isn't an end of the permutation
dp[i][j][k][m] += (2 * j - m) * dp[i - 1][j][k - cost_diff][m];
// Case 4: we append a[i] to the end of a component so that it's an end of the permutation
if (m == 1) dp[i][j][k][m] += 2 * j * dp[i - 1][j][k - cost_diff][m - 1];
if (m == 2) {
if (i == n) dp[i][j][k][m] += dp[i - 1][j][k - cost_diff][m - 1];
else if (j > 1) dp[i][j][k][m] += (j - 1) * dp[i - 1][j][k - cost_diff][m - 1];
}
// Case 5: we join two components
if (m == 2) {
if (i == n)
dp[i][j][k][m] += dp[i - 1][j + 1][k - cost_diff][m];
else
dp[i][j][k][m] += j * (j - 1) * dp[i - 1][j + 1][k - cost_diff][m];
} else if (m == 1)
dp[i][j][k][m] += j * j * dp[i - 1][j + 1][k - cost_diff][m];
else
dp[i][j][k][m] += j * (j + 1) * dp[i - 1][j + 1][k - cost_diff][m];
dp[i][j][k][m] %= MOD;
// if (dp[i][j][k][m]) cout << i << ' ' << j << ' ' << k << ' ' << m << ' ' << dp[i][j][k][m] << '\n';
}
}
}
}
ll ans = 0;
for (int i = 0; i <= l; i++) ans += dp[n][1][i][2];
cout << ans;
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
748 KB |
Output is correct |
| 2 |
Correct |
1 ms |
748 KB |
Output is correct |
| 3 |
Correct |
1 ms |
1024 KB |
Output is correct |
| 4 |
Correct |
1 ms |
748 KB |
Output is correct |
| 5 |
Correct |
1 ms |
876 KB |
Output is correct |
| 6 |
Correct |
1 ms |
876 KB |
Output is correct |
| 7 |
Correct |
1 ms |
748 KB |
Output is correct |
| 8 |
Correct |
1 ms |
876 KB |
Output is correct |
| 9 |
Incorrect |
1 ms |
876 KB |
Output isn't correct |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
