Submission #399609

#	Time	Username	Problem	Language	Result	Execution time	Memory
399609		cadmiumsky	Rack (eJOI19_rack)	C++14	100 / 100	9 ms	8128 KiB

rack

#include <iostream>
#define mod 1000000007
#define int unsigned long long


using namespace std;

int p2[1000001];

int n;

static int getnum(int poz, int step, int val=0) {
  if(step==n)
    return val;
  if((n-step-1)<=63) {
    //cout << step << '\n';
    if(poz>=(1ULL<<(n-step-1))) {
      //cout << "ok\n";
      val=(val+p2[step])%mod;
      poz-=(1ULL<<(n-step-1));
    }
  }
  return getnum(poz,step+1,val);
}

signed main() {
  p2[0]=1;
  for(int i=1; i<=1000000; i++)
    p2[i]=((long long)p2[i-1]*2LL)%mod;
  int k;
  cin >> n >> k;
  cout << 1+getnum(k-1,0) <<'\n';
  return 0;
}




/*
 * 
 * 
 * uiateasb
 * 
 * abcd
 * gggabggd
 * 
 * 
 * T[i][j] == daca am i caractere din s (primele)
 *      si alte j din t, care ar fi lungimea
 * 
 * T[i][j] = max( max (T[i][j-1], T[i-1][j]) , 
 *                T[i-1][j-1] (daca ultimele doua sunt egale)
 *   agcda 
 * a xxxxx 
 * b xxxxx
 * c xxo
 *   ac
 * T[4][8]=3
 */ 

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60