Submission #1097486

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097486		vjudge1	Rack (eJOI19_rack)	C++17	40 / 100	1 ms	348 KiB

rack

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

using ll = long long;

int MOD = 1e9 + 7;

ll log2_floor(unsigned long long x) {
    return x ? __builtin_clzll(1) - __builtin_clzll(x) : -1;
}

ll powmod(ll b, ll p) {
    if (!p) return 1;
    long long p2 = pow(b, p >> 1);
    return (1LL * p2 * p2 * (p & 1 ? b : 1)) % MOD;
}

ll test(ll n, ll k) {
    k--;
    ll result = 1;

    while (k) {
        ll mask = k & (-k);
        result = (result + powmod(2, n - log2_floor(mask) - 1)) % MOD;
        k ^= mask;
    }

    return result % MOD;
}

int main() {
    ll n, k;
    scanf("%d %d", &n, &k);
    printf("%d\n", test(n, k));
    return 0;
}

Compilation message (stderr)

rack.cpp: In function 'int main()':
rack.cpp:33:13: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'll*' {aka 'long long int*'} [-Wformat=]
   33 |     scanf("%d %d", &n, &k);
      |            ~^      ~~
      |             |      |
      |             int*   ll* {aka long long int*}
      |            %lld
rack.cpp:33:16: warning: format '%d' expects argument of type 'int*', but argument 3 has type 'll*' {aka 'long long int*'} [-Wformat=]
   33 |     scanf("%d %d", &n, &k);
      |               ~^       ~~
      |                |       |
      |                int*    ll* {aka long long int*}
      |               %lld
rack.cpp:34:14: warning: format '%d' expects argument of type 'int', but argument 2 has type 'll' {aka 'long long int'} [-Wformat=]
   34 |     printf("%d\n", test(n, k));
      |             ~^     ~~~~~~~~~~
      |              |         |
      |              int       ll {aka long long int}
      |             %lld
rack.cpp:33:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~

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