Submission #1117568

#	Time	Username	Problem	Language	Result	Execution time	Memory
1117568		ntdaccode	Magneti (COCI21_magneti)	C++17	110 / 110	89 ms	8700 KiB

Main

#include<bits/stdc++.h>
#define fori(i,a,b) for(int i=a;i<=b;i++)
#define int long long
#define pb push_back

using namespace std;

typedef pair<int,int> ii;
typedef tuple<int,int,int> tp;

const int M = 1e4 + 10;
const int N = 55;
const int mod = 1e9 + 7;

int n,l,r[N];
int f[2][N][M];

int power(int a,int n)
{
   if(n == 0) return 1;
   int t = power(a,n/2);
   t = (t * t) % mod;
   if(n % 2) t = (t * a) % mod;
   return t;
}

int fact[M],ifact[M];
void tohop(int x = 1e4)
{
   fact[0] = 1;
   for(int i = 1;i <= x; i++) fact[i] = (fact[i - 1] * i) % mod;
   ifact[x] = power(fact[x],mod - 2);
   for(int i = x - 1;i >= 0; i--) {
      ifact[i] = (ifact[i + 1] * (i + 1)) % mod;
   }
}

int C(int k,int n)
{
   if(k > n) return 0;
   int res = 1;
   res = (res * fact[n]) % mod;
   res = (res * ifact[n - k]) % mod;
   res = (res * ifact[k]) % mod;
   return res;
}

void add(int &x,int y)
{
   x += y;
   while(x >= mod) x -= mod;
}

int32_t main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);

  if(fopen("1.inp","r")) {
    freopen("1.inp","r",stdin);
    freopen("1.out","w",stdout);
  }

  #define task ""
  if(fopen(task".inp","r")) {
    freopen(task".inp","r",stdin);
    freopen(task".out","w",stdout);
  }

  cin >> n >> l;
  for(int i = 1;i <= n; i++) cin >> r[i];

  sort(r + 1, r + n + 1);

  f[0][0][0] = 1;
  for(int i = 1;i <= n; i++) {
      for(int j = 1;j <= min(i,(n+1)/2) ; j++) {
         for(int e = 0;e <= l; e++) {

            if(e >= r[i]) add(f[i&1][j][e],2 * j * f[i-1&1][j][e - r[i]]);

            if(e >= 2 * r[i] - 1) add(f[i&1][j][e], (j + 1) * j * f[i-1&1][j + 1][e - 2 * r[i] + 1]);

            add(f[i&1][j][e], f[i-1&1][j - 1][e - 1]);
         }
      }

      for(int j = 0;j <= i; j++)
         for(int e = 0;e <= l; e++) f[i-1&1][j][e] = 0;
  }

  tohop();

  int kq = 0;
  for(int i = 0;i <= l ; i++) {
      kq = (kq + f[n&1][1][i] * C(n, l + n - i ) % mod ) % mod;
      //cout << f[n&1][1][i] << " " <<i << "\n";
  }

  cout << kq;




}

Compilation message (stderr)

Main.cpp: In function 'int32_t main()':
Main.cpp:81:55: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   81 |             if(e >= r[i]) add(f[i&1][j][e],2 * j * f[i-1&1][j][e - r[i]]);
      |                                                      ~^~
Main.cpp:83:70: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   83 |             if(e >= 2 * r[i] - 1) add(f[i&1][j][e], (j + 1) * j * f[i-1&1][j + 1][e - 2 * r[i] + 1]);
      |                                                                     ~^~
Main.cpp:85:34: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   85 |             add(f[i&1][j][e], f[i-1&1][j - 1][e - 1]);
      |                                 ~^~
Main.cpp:90:40: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   90 |          for(int e = 0;e <= l; e++) f[i-1&1][j][e] = 0;
      |                                       ~^~
Main.cpp:61:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |     freopen("1.inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~
Main.cpp:62:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |     freopen("1.out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~
Main.cpp:67:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |     freopen(task".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:68:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |     freopen(task".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 50 / 50