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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#432925 | #8761. 另一个计数问题 | qzez | WA | 0ms | 17964kb | C++14 | 2.2kb | 2024-06-07 20:41:25 | 2024-06-07 20:41:26 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include"debug.h"
#else
#define debug(...) void()
#endif
#define all(x) (x).begin(),(x).end()
template<class T>
auto ary(T *a,int l,int r){
return vector<T>{a+l,a+1+r};
}
using ll=long long;
using ull=unsigned ll;
const int N=sqrt(1e11)+5,M=N*2,mod=998244353;
ll n;
struct node{
int x,y;
node(int a=0,int b=0):x(a),y(b){}
};
#ifdef DEBUG
ostream& operator << (ostream &out,node a){
return out<<make_pair(a.x,a.y);
}
#endif
node operator + (const node &a,const node &b){
return node((a.x+b.x)%mod,(a.y+b.y)%mod);
}
node operator - (const node &a,const node &b){
return node((a.x+mod-b.x)%mod,(a.y+mod-b.y)%mod);
}
node operator * (const node &a,const node &b){
return node(1ll*a.x*b.x%mod,1ll*a.y*b.y%mod);
}
int cnt,pri[N],vis[N];
node pre[N];
void init(int n){
fill(vis,vis+1+n,0),cnt=0;
for(int i=2;i<=n;i++){
if(!vis[i])pri[++cnt]=i;
for(int j=1;j<=cnt&&i*pri[j]<=n;j++){
vis[i*pri[j]]=1;
if(i%pri[j]==0)break;
}
}
for(int i=1;i<=cnt;i++){
pre[i]=pre[i-1]+node(pri[i],1ll*pri[i]*pri[i]%mod);
}
}
node f[M];
ll val[M];
int k,id1[N],id2[N];
int getid(ll x){
if(x*x<=n)return id1[x];
else return id2[n/x];
}
int sum1(ll x){
x%=mod;
return x*(x+1)/2%mod;
}
int sum2(ll x){
x%=mod;
return x*(x+1)%mod*(x+x+1)%mod*((mod+1)/6)%mod;
}
node calc(ll n){
::n=n;
if(!n)return node();
init(sqrtl(n)),k=0;
for(ll l=1,r;l<=n;l=r+1){
r=n/(n/l);
ll x=n/l;
if(x<=n/x)val[id1[x]=++k]=x;
else val[id2[n/x]=++k]=x;
}
for(int i=1;i<=k;i++)f[i]=node(sum1(val[i])-1,sum2(val[i])-1);
// debug(ary(val,1,k));
// debug(ary(f,1,k));
// debug(cnt,ary(pri,1,cnt));
for(int i=1;i<=cnt;i++){
node x=node(pri[i],1ll*pri[i]*pri[i]%mod);
for(int j=1;j<=k&&val[j]>=pri[i];j++){
f[j]=f[j]-x*f[getid(val[j]/pri[i])]+x*pre[i-1];
}
// debug(ary(f,1,k),x,pre[i-1]);
}
debug("calc",n,f[getid(n)]);
return f[getid(n)];
}
int main(){
ll n;
cin>>n;
// debug(n,getid(n));
// debug(f[getid(n)]);
node res=calc(n)-calc(n/2);
int sum=(sum1(n)-1-res.x+mod)%mod;
int ans=(sum2(n)-1-res.y+mod)%mod;
ans=(1ll*sum*sum+mod-ans)%mod*((mod+1)/2)%mod;
cout<<ans<<endl;
return 0;
}
#ifdef DEBUG
#include"debug.hpp"
#endif
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 15928kb
input:
4
output:
8
result:
ok 1 number(s): "8"
Test #2:
score: 0
Accepted
time: 0ms
memory: 15916kb
input:
5
output:
8
result:
ok 1 number(s): "8"
Test #3:
score: 0
Accepted
time: 0ms
memory: 15916kb
input:
6
output:
80
result:
ok 1 number(s): "80"
Test #4:
score: 0
Accepted
time: 0ms
memory: 17964kb
input:
7
output:
80
result:
ok 1 number(s): "80"
Test #5:
score: 0
Accepted
time: 0ms
memory: 15884kb
input:
8
output:
200
result:
ok 1 number(s): "200"
Test #6:
score: 0
Accepted
time: 0ms
memory: 13976kb
input:
9
output:
407
result:
ok 1 number(s): "407"
Test #7:
score: 0
Accepted
time: 0ms
memory: 13964kb
input:
10
output:
937
result:
ok 1 number(s): "937"
Test #8:
score: -100
Wrong Answer
time: 0ms
memory: 13940kb
input:
79
output:
3493623
result:
wrong answer 1st numbers differ - expected: '3224298', found: '3493623'