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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#129173#6740. FunctionNicolas125841WA 682ms249864kbC++171.5kb2023-07-22 04:29:572023-07-22 04:29:58

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2023-07-22 04:29:58]
  • 评测
  • 测评结果:WA
  • 用时:682ms
  • 内存:249864kb
  • [2023-07-22 04:29:57]
  • 提交

answer

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll mod = 998244353;
const int N = 20210926;
const int SB = 32;

vector<vector<ll>> stirl(SB + 1, vector<ll>(SB + 1, 0));
vector<ll> bell(SB+1, 0), pref(N+1);
vector<int> lp(N+1), pr;

void prep(){
    for (int i=2; i <= N; ++i) {
        if (lp[i] == 0) {
            lp[i] = i;
            pr.push_back(i);
        }
        for (int j = 0; i * pr[j] <= N; ++j) {
            lp[i * pr[j]] = pr[j];
            if (pr[j] == lp[i]) {
                break;
            }
        }
    }
    
    for(int i = 1; i <= SB; i++){
        stirl[i][i] = 1;
        stirl[i][1] = 1;
    }

    for(int n = 2; n <= SB; n++){
        for(int k = 2; k <= n; k++){
            stirl[n][k] = (stirl[n-1][k-1] + k * stirl[n-1][k]) % mod;
        }
    }

    for(int n = 1; n <= SB; n++){
        for(int k = 1; k <= n; k++){
            bell[n] += stirl[n][k];
        }

        bell[n] %= mod;
    }

    pref[0] = 0;
    pref[1] = 1;

    for(int i = 2; i <= N; ++i){
        pref[i] = pref[i-1];

        int ti = i;
        int cnt = 0;

        while(ti != 1){
            cnt++;
            ti /= lp[ti];
        }

        pref[i] += bell[cnt];
        pref[i] %= mod;
    }
}

int main(){
    prep();

    int n;
    cin >> n;

    ll ans = 0;

    for(int i = 1; i <= n; i++){
        ans += pref[i] - pref[i-1];
    }

    cout << ans << "\n";
}

Details

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Test #1:

score: 100
Accepted
time: 660ms
memory: 249864kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 669ms
memory: 249208kb

input:

2

output:

2

result:

ok 1 number(s): "2"

Test #3:

score: -100
Wrong Answer
time: 682ms
memory: 248868kb

input:

100

output:

998

result:

wrong answer 1st numbers differ - expected: '949', found: '998'