#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
const int mod = (int)1e9+7;
struct Mint{
int val;
Mint(){ val = 0; }
Mint(long long v){
val = (-mod <= v && v < mod) ? v : v%mod;
if(val < 0) val+= mod;
}
// operators
Mint operator-(){return Mint(-val);}
Mint& operator+=(const Mint& other){ val+=other.val; if(val >= mod) val-=mod; return *this;}
Mint& operator-=(const Mint& other){ val-=other.val; if(val < 0) val+=mod; return *this;}
Mint& operator*=(const Mint& other){ val=((long long)val*other.val)%mod; return *this;}
friend Mint binpow(Mint a, long long p){
Mint res(1);
while(p > 0){
if(p&1) res*=a; a*=a; p>>=1;
}
return res;
}
friend Mint inv(Mint a){ return binpow(a, mod-2); }
Mint& operator/=(const Mint &other){ return (*this)*=inv(other);}
friend Mint operator+(Mint a, const Mint& b){ return a+=b; }
friend Mint operator-(Mint a, const Mint& b){ return a-=b; }
friend Mint operator*(Mint a, const Mint& b){ return a*=b; }
friend Mint operator/(Mint a, const Mint& b){ return a/=b; }
bool operator==(const Mint &other){return val == other.val;}
bool operator!=(const Mint &other){return val != other.val;}
bool operator<(const Mint &other){return val < other.val;}
// io
friend ostream& operator<<(ostream &out, Mint &a){ return out << a.val; }
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
int n, l;
cin >> n >> l;
vi a(n); cin >> a;
sort(all(a)); a.pb(10000);
array<Mint, 3> zr = {0, 0, 0};
vector<vector<array<Mint, 3>>> dp(n + 5, vector<array<Mint, 3>>(l + 1, zr));
vector<vector<array<Mint, 3>>> new_dp(n + 5, vector<array<Mint, 3>>(l + 1, zr));
if(n == 1){
cout << 1 << "\n";
return 0;
}
if(a[1] - a[0] <= l) dp[1][a[1] - a[0]][1] = Mint(2);
if(2 * (a[1] - a[0]) <= l) dp[1][2 * (a[1] - a[0])][0] = Mint(1);
FOR(i, 1, n, 1){
int df = a[i + 1] - a[i];
FOR(j, 1, i + 1, 1){
FOR(k, 0, l + 1, 1){
REP(e, 3){
if(e < 2 && k + df * (2 * j - e - 1) <= l){
if(i == n - 1){
new_dp[j][k + df*(2 * j - e - 1)][e + 1] += dp[j][k][e] * Mint(j) * Mint(2 - e);
}
else if(e == 0 || j > 1){
new_dp[j][k + df * (2 * j - e - 1)][e + 1] += dp[j][k][e] * Mint(2 - e) * Mint(j - e);
}
if(k + df * (2 * j - e + 1) <= l){
new_dp[j + 1][k + df * (2 * j - e + 1)][e + 1] += dp[j][k][e] * Mint(2 - e);
}
}
if(k + df * (2 * j + 2 - e) <= l){
new_dp[j + 1][k + df * (2 * j + 2 - e)][e] += dp[j][k][e];
}
if(k + df * (2 * j - e) <= l){
new_dp[j][k + df * (2 * j - e)][e] += dp[j][k][e] * Mint(2 * j - e);
}
if((k + df * (2 * j - 2 - e) <= l) && (j >= 2) && (i == n - 1 || j > 2 || e < 2)){
if(e == 0){
new_dp[j - 1][k + df * (2 * j - 2 - e)][e] += dp[j][k][e] * Mint(j) * Mint(j - 1);
}
if(e == 1){
new_dp[j - 1][k + df * (2 * j - 2 - e)][e] += dp[j][k][e] * Mint(j - 1) * Mint(j - 1);
}
if(e == 2){
if(i == n - 1){
new_dp[j - 1][k + df * (2 * j - e - 2)][e] += dp[j][k][e];
}
else{
new_dp[j - 1][k + df * (2 * j - e - 2)][e] += dp[j][k][e] * (Mint(2) * Mint(j - 2) + Mint(j - 2) * Mint(j - 3));
}
}
}
}
}
}
dp.swap(new_dp);
REP(j, i + 1){
FOR(k, 0, l + 1, 1){
REP(e, 3)
new_dp[j][k][e] = Mint(0);
}
}
}
Mint res(0);
REP(s, l + 1) res += dp[1][s][2];
cout << res << "\n";
return 0;
}
Compilation message
skyscraper.cpp: In function 'Mint binpow(Mint, long long int)':
skyscraper.cpp:101:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
101 | if(p&1) res*=a; a*=a; p>>=1;
| ^~
skyscraper.cpp:101:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
101 | if(p&1) res*=a; a*=a; p>>=1;
| ^
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
1 ms |
364 KB |
Output is correct |
| 4 |
Correct |
1 ms |
364 KB |
Output is correct |
| 5 |
Correct |
2 ms |
620 KB |
Output is correct |
| 6 |
Correct |
1 ms |
620 KB |
Output is correct |
| 7 |
Correct |
1 ms |
364 KB |
Output is correct |
| 8 |
Correct |
1 ms |
492 KB |
Output is correct |
| 9 |
Correct |
2 ms |
620 KB |
Output is correct |
| 10 |
Correct |
1 ms |
364 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
1 ms |
364 KB |
Output is correct |
| 4 |
Correct |
1 ms |
364 KB |
Output is correct |
| 5 |
Correct |
1 ms |
364 KB |
Output is correct |
| 6 |
Correct |
1 ms |
364 KB |
Output is correct |
| 7 |
Correct |
1 ms |
492 KB |
Output is correct |
| 8 |
Correct |
1 ms |
384 KB |
Output is correct |
| 9 |
Correct |
1 ms |
384 KB |
Output is correct |
| 10 |
Correct |
1 ms |
364 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
1 ms |
364 KB |
Output is correct |
| 4 |
Correct |
1 ms |
364 KB |
Output is correct |
| 5 |
Correct |
2 ms |
620 KB |
Output is correct |
| 6 |
Correct |
1 ms |
620 KB |
Output is correct |
| 7 |
Correct |
1 ms |
364 KB |
Output is correct |
| 8 |
Correct |
1 ms |
492 KB |
Output is correct |
| 9 |
Correct |
2 ms |
620 KB |
Output is correct |
| 10 |
Correct |
1 ms |
364 KB |
Output is correct |
| 11 |
Correct |
1 ms |
364 KB |
Output is correct |
| 12 |
Correct |
1 ms |
364 KB |
Output is correct |
| 13 |
Correct |
1 ms |
364 KB |
Output is correct |
| 14 |
Correct |
1 ms |
364 KB |
Output is correct |
| 15 |
Correct |
1 ms |
364 KB |
Output is correct |
| 16 |
Correct |
1 ms |
364 KB |
Output is correct |
| 17 |
Correct |
1 ms |
492 KB |
Output is correct |
| 18 |
Correct |
1 ms |
384 KB |
Output is correct |
| 19 |
Correct |
1 ms |
384 KB |
Output is correct |
| 20 |
Correct |
1 ms |
364 KB |
Output is correct |
| 21 |
Correct |
2 ms |
364 KB |
Output is correct |
| 22 |
Correct |
191 ms |
1900 KB |
Output is correct |
| 23 |
Correct |
247 ms |
2944 KB |
Output is correct |
| 24 |
Correct |
206 ms |
2156 KB |
Output is correct |
| 25 |
Correct |
239 ms |
2796 KB |
Output is correct |
| 26 |
Correct |
221 ms |
2412 KB |
Output is correct |
| 27 |
Correct |
75 ms |
1132 KB |
Output is correct |
| 28 |
Correct |
97 ms |
1132 KB |
Output is correct |
| 29 |
Correct |
187 ms |
1772 KB |
Output is correct |
| 30 |
Correct |
247 ms |
2816 KB |
Output is correct |
