#include <set>
#include <map>
#include <cmath>
#include <queue>
#include <deque>
#include <stack>
#include <math.h>
#include <bitset>
#include <vector>
#include <string>
#include <cstdio>
#include <cctype>
#include <numeric>
#include <fstream>
#include <sstream>
#include <cstdlib>
#include <iomanip>
#include <cassert>
#include <cstring>
#include <stdio.h>
#include <string.h>
#include <iterator>
#include <iostream>
#include <algorithm>
#include <strings.h>
#include <functional>
#include <unordered_set>
#include <unordered_map>
#define fore(i, a, b) for (int i = (a), i##_last = (b); i < i##_last; ++i)
#define fort(i, a, b) for (int i = (a), i##_last = (b); i <= i##_last; ++i)
#define ford(i, a, b) for (int i = (a), i##_last = (b); i >= i##_last; --i)
#define fi first
#define se second
#define pb push_back
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using namespace std;
using ll = long long;
using ld = long double;
template<class A, class B> bool maxi(A &a, const B &b) {return (a < b) ? (a = b, true):false;};
template<class A, class B> bool mini(A &a, const B &b) {return (a > b) ? (a = b, true):false;};
typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
constexpr int MAX_N = 1E6 + 6, MOD = 1E9 + 7;
const ll INF = 0X3F3F3F3F3F3F3F3F;
signed result, p[MAX_N];
ll k, r[MAX_N];
int n;
/*
Idea:
At a node, if the weights of two children branches are equal than
go to left branch
Otherwise
go to right branch
Observation:
At i-th level
there is power(2, i - 1) direct branches from the immediately above level
and every branch of these branches will be visited before
any branch is visited again
This means that,
there will be power(2, i - 1) times of choosing the left child branch
then power(2, i - 1) times of choosing the right child branch
then again ... (continue the cycle)
*/
signed main() {
#ifdef LOCAL
freopen("input.INP", "r", stdin);
// freopen("output.OUT", "w", stdout);
#endif // LOCAL
cin.tie(0) -> sync_with_stdio(0);
cout.tie(0);
cin >> n >> k;
p[0] = r[0] = 1;
fort(i, 1, n) {
p[i] = (p[i - 1] << 1) % MOD;
r[i] = min(r[i - 1] << 1, INF);
}
for (int i = n - 1, j = 0; i >= 0; --i, ++j)
if (((k - 1) / r[j]) & 1)
(result += p[i]) %= MOD;
(++result) %= MOD;
cout << result << '\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
460 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
1 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
460 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
1 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
1 ms |
344 KB |
Output is correct |
12 |
Correct |
1 ms |
600 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
1 ms |
1048 KB |
Output is correct |
15 |
Correct |
10 ms |
11824 KB |
Output is correct |