#include <bits/stdc++.h> #define long long long using namespace std; const int N = 105; const int L = 1e3+5; const int M = 1e9+7; int n, l, a[N]; long dp[N][N][L][3]; long solve(int pos, int cc, int diff, int ends) { if(pos == n + 1) return (cc == 1 && diff <= l && ends == 2); if(cc == 0 || diff > l || ends == 3) return 0; long &now = dp[pos][cc][diff][ends]; if(~now) return now; int ndiff = diff + (a[pos] - a[pos - 1]) * (2 * cc - ends); now = 0; now = (now + (cc + 1 - ends) * solve(pos + 1, cc + 1, ndiff, ends) % M) % M; now = (now + (2 * cc - ends) * solve(pos + 1, cc, ndiff, ends) % M) % M; now = (now + (cc - 1) * solve(pos + 1, cc - 1, ndiff, ends) % M) % M; now = (now + (2 - ends) * solve(pos + 1, cc + 1, ndiff, ends + 1) % M) % M; now = (now + (2 - ends) * solve(pos + 1, cc, ndiff, ends + 1) % M) % M; return now; } int main() { memset(dp, -1, sizeof dp); scanf("%d %d", &n, &l); for(int i = 1; i <= n; i++) scanf("%d", a + i); sort(a + 1, a + n + 1); if(n == 1) return !printf("1\n"); printf("%lld\n", (solve(2, 1, 0, 0) + 2 * solve(2, 1, 0, 1)) % M); return 0; }

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &l);
     ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:36:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1; i <= n; i++) scanf("%d", a + i);
                                 ~~~~~^~~~~~~~~~~~~