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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#106774 | #3161. Another Coin Weighing Puzzle | marsxiang5902# | WA | 2ms | 3484kb | C++17 | 647b | 2023-05-19 06:35:54 | 2023-05-19 06:35:58 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MN = 1e6+5, MOD = 1e9+7;
ll fpow(ll b, int e=MOD-2) {
ll ret = 1;
for (; e; e>>=1) {
if (e&1) ret = ret*b %MOD;
b = b*b %MOD;
} return ret;
}
int N, M, pfs[MN]; vector<int> primes;
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> M;
ll ans = 0;
for (int i = 2; i <= M; i++) {
if (!pfs[i])
for (int j = i; j <= M; j += i)
++pfs[j];
ans += (pfs[i]&1 ? 1 : -1) * (fpow(M/i*2+1, N) - 1);
}
ans = fpow(M*2+1, N) - ans;
printf("%lld\n", (ans%MOD+MOD)%MOD);
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 2ms
memory: 3464kb
input:
2 1
output:
9
result:
ok single line: '9'
Test #2:
score: 0
Accepted
time: 2ms
memory: 3468kb
input:
2 2
output:
17
result:
ok single line: '17'
Test #3:
score: -100
Wrong Answer
time: 2ms
memory: 3484kb
input:
10000 10000
output:
589049894
result:
wrong answer 1st lines differ - expected: '689223145', found: '589049894'