#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; #define int long long #define ll long long #define ld long double #define endl '\n' #define wady \ ios_base::sync_with_stdio(0); \ cin.tie(0); \ cout.tie(0); void files() { #ifndef ONLINE_JUDGE freopen("in.txt", "r", stdin); freopen("out.txt", "w", stdout); #endif } const int N = 1e2 + 5, mod = 1e9 + 7; int dp[N][N][10 * N][5], a[N]; int n, l; int add(ll a,ll b) { return (a + b) % mod; } int mul(ll a,ll b) { return (a * b) % mod; } int rec(int idx, int open, int sum, int last) { if (last > 2 or sum > l)return 0; if (open == 0 and idx > 1)return 0; if (idx == n + 1) { return last == 2 and open == 1; } int &ret = dp[idx][open][sum][last]; if (~ret)return ret; ret = 0; int nsum = sum + (a[idx] - a[idx - 1]) * (2 * open - last); if (open >= 2) { ret = add(ret, mul(open - 1, rec(idx + 1, open - 1, nsum, last))); } if (open >= 1) { ret = add(ret, mul(2 * open - last, rec(idx + 1, open, nsum, last))); } ret = add(ret, mul(open + 1 - last, rec(idx + 1, open + 1, nsum, last))); if (last < 2) { ret = add(ret, mul(2 - last, rec(idx + 1, open + 1, nsum, last + 1))); } if (last < 2) { ret = add(ret, mul(2 - last, rec(idx + 1, open, nsum, last + 1))); } return ret; } void solve(int tc) { cin >> n >> l; for (int i = 1; i <= n; i++) cin >> a[i]; sort(a + 1, a + 1 + n); if (n == 1)return cout << "1\n", void(); memset(dp, -1, sizeof dp); cout << rec(1, 0, 0, 0) % mod << endl; } signed main() { wady // files(); int t = 1; // cin >> t; int tc = 1; while (t--) solve(tc++); }

skyscraper.cpp: In function 'void files()':
skyscraper.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen("in.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     freopen("out.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~