Submission #977244

#	Time	Username	Problem	Language	Result	Execution time	Memory
977244		vahagng	Rack (eJOI19_rack)	C++17	100 / 100	1 ms	360 KiB

rack

//----------vahagng----------//
#define CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

// Defines

#define ll long long
#define all(v) v.begin(), v.end()
#define pii pair<int, int>
#define ppb pop_back
#define pb push_back
#define mii map<int, int>
#define mll map<long long, long long>
#define no_ans cout << -1 << '\n';
#define YES cout << "YES\n";
#define NO cout << "NO\n";
#define ok cout << "OK\n";

// Constants 

const ll N = 3e5 + 10, M = 105;
const ll inf = 1e18, mod = 1000000007;

// Functions

void SetIO(string str = "") {
    if (str != "") {
        freopen((str + ".in").c_str(), "r", stdin);
        freopen((str + ".out").c_str(), "w", stdout);
    } else {
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    }
}
 
void FastIO() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}

ll add(ll a, ll b)
{
    return (a + b)%mod;
}

ll mult(ll a, ll b)
{
    return (a%mod * b%mod)%mod;
}

ll sub(ll a, ll b)
{
    return (a - b + 2*mod)%mod;
}

long long binpower(long long a, long long n) {
	if(n == 0) {
		return 1;
	}
 
	if(n == 1) {
		return a;
	}
 
	if(n % 2 == 1) {
		long long curr = binpower(a, n / 2);
		curr = mult(curr, curr);
		curr = mult(a, curr);
		return curr;
	} else {
		long long curr = binpower(a, n / 2);
		return mult(curr, curr);
	}
}

ll power(int a, int b)
{
    ll res = 1;
    while(b--)
    {
        res*=a;
    }
    return res;
}

// const int N = 2e5 + 10;
// pair<int,int>max_dist;
// vector<int>adj[N];
// int dists[N];

// void dfs(int node, int parent, int dist) 
// {
//     dists[node] = max(dists[node], dist);
// 	if(dist > max_dist.first) 
//     {
// 		max_dist = {dist, node};
// 	}
 
// 	for(auto i: adj[node]) 
//     {
// 		if(i == parent) continue;
// 		dfs(i, node, dist + 1);
// 	}
// }
 
// pair<int, int> get_farthest_distance(int node) 
// {
// 	max_dist = {-1, -1};
// 	dfs(node, -1, 0);
// 	return max_dist;
// }

void precision(int x)
{
	cout.setf(ios::fixed | ios::showpoint);
	cout.precision(x);
	return;
}

ll ceil_division(ll a, ll b)
{
    return (a + b - 1) / b;
}

ll digit_sum(int n)
{
    ll sum = 0;
    for(int i = 1; i * i <= n; i++)
    {
        if(n%i == 0)
        {
            sum += i;
            if(n/i == i || n / i == n) continue;
            sum += (n/i);
        }
    }
    return sum;
}

ll lcm(ll a, ll b)
{
    return a / gcd(a, b) * b;
}

// Solution

ll n, q;

/*
5 6
1 2 3 4 5
2 1 3
1 1 3
2 1 5
2 4 4
1 1 1
2 4 4
*/

void solve()
{
    cin >> n >> q;
    q--;
    ll z = n-1;
    ll ans = 0;
    while(q)
    {
        if(q&1) ans = add(ans, binpower(2, z));
        z--;
        q>>=1;
    }
    ans = add(ans, 1);
    cout << ans << '\n';
}

void precalc()
{
    
}

int main()
{
    FastIO();
    precalc();
    int test_case = 1;
    // cin >> test_case;
    while (test_case--) 
    {
        solve();
    }
    return 0;
}

Compilation message (stderr)

rack.cpp: In function 'void SetIO(std::string)':
rack.cpp:33:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen((str + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
rack.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         freopen((str + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
rack.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
rack.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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