Submission #1211246

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211246		nguyn	Rack (eJOI19_rack)	C++20	40 / 100	0 ms	328 KiB

rack

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ll long long 
#define F first
#define S second
#define pb push_back 
#define pii pair<int,int>

const int N = 1e6 + 5;
const int mod = 1e9 + 7;

int n, k;
int pw[N];

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

signed main(){
    ios_base::sync_with_stdio(false) ; 
    cin.tie(0) ; cout.tie(0) ; 
    if (fopen("INP.INP" ,"r")) {
        freopen("INP.INP" ,"r" , stdin) ;
        freopen("OUT.OUT" , "w" , stdout) ;
    }
    cin >> n >> k;
    // if (n <= 20) {
	//     vector<int> cur;
	//     cur.pb(1); 
	//     for (int i = (1 << (n - 1)); i >= 1; i >>= 1) {
	//     	int sz = cur.size();
	//     	for (int j = 0; j < sz; j++) {
	//     		cur.pb(cur[j] + i); 
	//     	}
	//     }
	//     // for (int i : cur) {
	//     // 	cout << i << ' '; 
	//     // }
	//     cout << cur[k - 1] << '\n'; 
	//     return 0;
    // }
    pw[0] = 1;
    for (int i = 1; i <= n; i++) {
    	pw[i] = pw[i - 1] + pw[i - 1];
    	if (pw[i] >= mod) pw[i] -= mod;
    }
    int res = 0; 
	for (int i = min(n, 60ll); i >= 0; i--) {
		if (k > (1 << i)) {
			int t = i + 1; 
			// cout << t << ' ' << pw[n - t] << '\n';
			add(res, pw[n - t]); 
			k -= (1 << i);
		}
	}
	cout << res + 1;
}

Compilation message (stderr)

rack.cpp: In function 'int main()':
rack.cpp:26:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |         freopen("INP.INP" ,"r" , stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
rack.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen("OUT.OUT" , "w" , stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 0 / 60