Submission #420770

#	Time	Username	Problem	Language	Result	Execution time	Memory
420770		qwerasdfzxcl	Asceticism (JOI18_asceticism)	C++14	100 / 100	58 ms	292 KiB

asceticism

#include <bits/stdc++.h>
 
typedef long long ll;
using namespace std;
const int MOD = 1e9+7;
 
ll pw(ll a, ll e){
    if (!e) return 1;
    ll ret = pw(a, e/2);
    if (e&1) return ret*ret%MOD*a%MOD;
    return ret*ret%MOD;
}
 
int main(){
    int n, k;
    scanf("%d %d", &n, &k);
    ll ans = 0, tmp = 1;
    for (int i=k;i;i--){
        ans = (ans+pw(i, n)*tmp)%MOD;
        tmp = (-tmp*(n+1-k+i)%MOD)*pw(k-i+1, MOD-2)%MOD;
        if (tmp<0) tmp += MOD;
    }
    printf("%lld\n", ans);
    return 0;
}

Compilation message (stderr)

asceticism.cpp: In function 'int main()':
asceticism.cpp:16:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 51 / 51